FACTOID # 17: Though Rhode Island is the smallest state in total area, it has the longest official name: The State of Rhode Island and Providence Plantations.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Technetium" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Technetium
43 molybdenumtechnetiumruthenium
Mn

Tc

Re
General
Name, Symbol, Number technetium, Tc, 43
Chemical series transition metals
Group, Period, Block 7, 5, d
Appearance silvery gray metal
Standard atomic weight [98](0) g·mol−1
Electron configuration [Kr] 4d5 5s2
Electrons per shell 2, 8, 18, 13, 2
Physical properties
Phase solid
Density (near r.t.) 11 g·cm−3
Melting point 2430 K
(2157 °C, 3915 °F)
Boiling point 4538 K
(4265 °C, 7709 °F)
Heat of fusion 33.29 kJ·mol−1
Heat of vaporization 585.2 kJ·mol−1
Heat capacity (25 °C) 24.27 J·mol−1·K−1
Vapor pressure (extrapolated)
P(Pa) 1 10 100 1 k 10 k 100 k
at T(K) 2727 2998 3324 3726 4234 4894
Atomic properties
Crystal structure hexagonal
Oxidation states 7
(strongly acidic oxide)
Electronegativity 1.9 (scale Pauling)
Electron affinity -53 kJ/mol
Ionization energies 1st: 702 kJ/mol
2nd: 1470 kJ/mol
3rd: 2850 kJ/mol
Atomic radius 135 pm
Atomic radius (calc.) 183 pm
Covalent radius 156 pm
Miscellaneous
Magnetic ordering Paramagnetic
Thermal conductivity (300 K) 50.6 W·m−1·K−1
CAS registry number 7440-26-8
Selected isotopes
Main article: Isotopes of technetium
iso NA half-life DM DE (MeV) DP
95mTc syn 61 d ε - 95Mo
γ 0.204, 0.582,
0.835
-
IT 0.0389, e 95Tc
96Tc syn 4.3 d ε - 96Mo
γ 0.778, 0.849,
0.812
-
97Tc syn 2.6×106 y ε - 97Mo
97mTc syn 90 d IT 0.965, e 97Tc
98Tc syn 4.2×106 y β- 0.4 98Ru
γ 0.745, 0.652 -
99Tc trace 2.111×105 y β- 0.294 99Ru
99mTc trace 6.01 h IT 0.142, 0.002 99Tc
γ 0.140 -
References

Technetium (pronounced /tɛkˈniːʃɪəm/) is the lightest chemical element with no stable isotope. It has atomic number 43 and is given the symbol Tc. The chemical properties of this silvery grey, crystalline transition metal are intermediate between rhenium and manganese. Its short-lived gamma-emitting nuclear isomer 99mTc (technetium-99m) is used in nuclear medicine for a wide variety of diagnostic tests. 99Tc is used as a gamma ray-free source of beta particles. The pertechnetate ion (TcO4-) could eventually be used[clarify] as a strong anodic corrosion inhibitor for mild steel in closed cooling systems. General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... General Name, Symbol, Number rhenium, Re, 75 Chemical series transition metals Group, Period, Block 7, 6, d Appearance grayish white Standard atomic weight 186. ... Key This is a diagram showing the location of an element in the wide version of the periodic table along with some other data. ... This is a standard display of the periodic table of the elements. ... An extended periodic table was suggested by Glenn T. Seaborg in 1969. ... This is a list of chemical elements, sorted by name and color coded according to type of element. ... A table of chemical elements ordered by atomic number and color coded according to type of element. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... In the periodic table of the elements, a period is a horizontal row of the table. ... A block of the periodic table of elements is a set of adjacent groups. ... A Group 7 element is an element in periodic table group 7 (IUPAC style) in the periodic table, which consists of: manganese (25) technetium (43) rhenium (75) bohrium (107) All of these elements are classed in Group 7 because their valence shell holds four electrons. ... A period 5 element is one of the chemical elements in the fifth row (or period) of the periodic table of the elements. ... D Block is a rap group based in Yonkers, New York. ... Color is an important part of the visual arts. ... Image File history File links Tc,43. ... The atomic mass (ma) is the mass of an atom at rest, most often expressed in unified atomic mass units. ... To help compare different orders of magnitude we list here masses between 60. ... Hydrogen = 1 List of Elements in Atomic Number Order. ... Electron atomic and molecular orbitals In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (, a crystal). ... For other uses, see Krypton (disambiguation). ... For other uses, see Electron (disambiguation). ... Example of a sodium electron shell model An electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... For other uses, see Solid (disambiguation). ... For other uses, see Density (disambiguation). ... For other uses, see Room temperature (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ... For other uses, see Kelvin (disambiguation). ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... For other uses, see Fahrenheit (disambiguation). ... Italic text This article is about the boiling point of liquids. ... For other uses, see Kelvin (disambiguation). ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... For other uses, see Fahrenheit (disambiguation). ... Standard enthalpy change of fusion of period three. ... The joule per mole (symbol: J·mol-1) is an SI derived unit of energy per amount of material. ... The standard enthalpy change of vaporization, ΔvHo, also (less correctly) known as the heat of vaporization is the energy required to transform a given quantity of a substance into a gas. ... The joule per mole (symbol: J·mol-1) is an SI derived unit of energy per amount of material. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... The oxidation number of an element in a molecule or complex is the charge that it would have if all the ligands (basically, atoms that donate electrons) were removed along with the electron pairs that were shared with the central atom[1]. It means that the oxidation number is the... For other uses, see Acid (disambiguation). ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... The electron affinity, Eea, of an atom or molecule is the energy required to detach an electron from a singly charged negative ion, i. ... The ionization energy (IE) of an atom or of a molecule is the energy required to strip it of an electron. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... Atomic radius: Ionic radius Covalent radius Metallic radius van der Waals radius edit Atomic radius, and more generally the size of an atom, is not a precisely defined physical quantity, nor is it constant in all circumstances. ... You have big harry skanky balls ... One picometre is defined as 1x10-12 metres, in standard units. ... You have big harry skanky balls ... Atomic radius: Ionic radius Covalent radius Metallic radius van der Waals radius edit The covalent radius, rcov, is a measure of the size of atom which forms part of a covalent bond. ... You have big harry skanky balls ... For other senses of this word, see magnetism (disambiguation). ... Paramagnetism is the tendency of the atomic magnetic dipoles, due to quantum-mechanical spin, in a material that is otherwise non-magnetic to align with an external magnetic field. ... K value redirects here. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Technetium (Tc) Has no stable isotopes. ... For other uses, see Isotope (disambiguation). ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... The decay energy is the energy released by a nuclear decay. ... The electronvolt (symbol eV) is a unit of energy. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... To help compare orders of magnitude of different times this page lists times between 106 seconds (a megasecond) and 107 seconds (11. ... Look up day in Wiktionary, the free dictionary. ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... This article is about electromagnetic radiation. ... . Internal conversion is a radioactive decay process where an excited nucleus interacts with an electron in one of the lower electron shells, causing the electron to be emitted from the atom. ... A conversion electron is an electron which results from interactions with metastable atomic nuclei, which results from radioactive decay processes. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... To help compare orders of magnitude of different times this page lists times between 105 seconds and 106 seconds (27. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... To help compare orders of magnitude of different times this page lists times between 320 000 years and 3 200 000 years (1013 seconds and 1014 seconds) See also times of other orders of magnitude. ... A year (from Old English gÄ“r) is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... To help compare orders of magnitude of different times this page lists times between 106 seconds (a megasecond) and 107 seconds (11. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... To help compare orders of magnitude of different times this page lists times between 3. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ... A trace radioisotope is a radioisotope that is naturally occurring. ... To help compare orders of magnitude of different times this page lists times between 32 000 years and 320 000 years (1012 seconds—a terasecond—and 1013 seconds). ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ... A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... A trace radioisotope is a radioisotope that is naturally occurring. ... To help compare orders of magnitude of different times this page lists times between 104 seconds and 105 seconds (2. ... The hour (symbol: h) is a unit of time. ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... Stable isotopes are chemical isotopes that are not radioactive. ... See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... General Name, Symbol, Number rhenium, Re, 75 Chemical series transition metals Group, Period, Block 7, 6, d Appearance grayish white Standard atomic weight 186. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... Technetium-99m is a metastable nuclear isomer of technetium-99, symbolized as 99mTc. ... Shown above is the bone scintigraphy of a young woman. ... General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Atomic mass (98) g/mol Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... This article is about electromagnetic radiation. ... Alpha radiation consists of helium nuclei and is readily stopped by a sheet of paper. ... The pertechnetate ion is TcO4-. A pertechnetate is a compound containing this ion. ... This article is about the electrically charged particle. ... For the hazard, see corrosive. ... For other uses, see Steel (disambiguation). ...


Before the element was discovered, many of the properties of element 43 were predicted by Dmitri Mendeleev. Mendeleev noted a gap in his periodic table and called the element ekamanganese. In 1937 its isotope 97Tc became the first predominantly artificial element to be produced, hence its name (from the Greek τεχνητός, meaning "artificial"). Most technetium produced on Earth is a by-product of fission of uranium-235 in nuclear reactors and is extracted from nuclear fuel rods. No isotope of technetium has a half-life longer than 4.2 million years (98Tc), so its detection in red giants in 1952 helped bolster the theory that stars can produce heavier elements. Note that on Earth, technetium occurs in trace but measurable quantities as a product of spontaneous fission in uranium ore or by neutron capture in molybdenum ores. Professor Dimitri Mendeleev published the first Periodic Table of the Atomic Elements in 1869 based on properties which appeared with some regularity as he laid out the elements from lightest to heaviest. ... Portrait of Dimitri Mendeleev by Ilya Repin (Russian: , Dimitri Ivanovich Mendeleev  ) (8 February [O.S. 27 January] 1834 in Tobolsk – 2 February [O.S. 20 January] 1907 in Saint Petersburg), was a Russian chemist. ... The Periodic Table redirects here. ... An induced nuclear fission event. ... Uranium-235 is an isotope of uranium that differs from the elements other common isotope, uranium-238, by its ability to cause a rapidly expanding fission chain reaction. ... Core of a small nuclear reactor used for research. ... The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giant stars. ... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... The process of neutron capture can proceed in two ways - as a rapid process (an r-process) or a slow process (an s-process). ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ...

Contents

Characteristics

Technetium is a silvery-grey radioactive metal with an appearance similar to platinum. However, it is commonly obtained as a grey powder. Its position in the periodic table is between rhenium and manganese and as predicted by the periodic law its properties are intermediate between those two elements. Technetium is unusual among the lighter elements in that it has no stable isotopes. Only technetium and promethium have no stable isotopes, but are followed by elements which do. This article is about metallic materials. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... General Name, Symbol, Number rhenium, Re, 75 Chemical series transition metals Group, Period, Block 7, 6, d Appearance grayish white Standard atomic weight 186. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... The periodic table is a tabular method of displaying the chemical elements. ... For other uses, see Isotope (disambiguation). ... General Name, Symbol, Number promethium, Pm, 61 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance metallic Atomic mass [145](0) g/mol Electron configuration [Xe] 4f5 6s2 Electrons per shell 2, 8, 18, 23, 8, 2 Physical properties Phase solid Density (near r. ...


Technetium is therefore extremely rare on Earth. Technetium plays no natural biological role and is not normally found in the human body. This article is about Earth as a planet. ... This article is about modern humans. ...


The metal form of technetium slowly tarnishes in moist air. Its oxides are TcO2 and Tc2O7. Under oxidizing conditions technetium (VII) will exist as the pertechnetate ion, TcO4-.[1] Common oxidation states of technetium include 0, +2, +4, +5, +6 and +7.[2] Technetium will burn in oxygen when in powder form.[3] It dissolves in aqua regia, nitric acid, and concentrated sulfuric acid, but it is not soluble in hydrochloric acid. It has characteristic spectral lines at 363 nm, 403 nm, 410 nm, 426 nm, 430 nm, and 485 nm.[4] Tarnish is a layer of corrosion that develops over copper, brass, silver, aluminum as well as a degree of semi-reactive metals as they undergo oxidation. ... An oxide is a chemical compound containing at least one oxygen atom and other elements. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... The pertechnetate ion is TcO4-. A pertechnetate is a compound containing this ion. ... This article is about the electrically charged particle. ... The oxidation number of an element in a molecule or complex is the charge that it would have if all the ligands (basically, atoms that donate electrons) were removed along with the electron pairs that were shared with the central atom[1]. It means that the oxidation number is the... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Freshly prepared aqua regia is colorless, but it turns orange within seconds. ... The chemical compound nitric acid (HNO3), also known as aqua fortis and spirit of nitre, is an aqueous solution of hydrogen nitrate (anhydrous nitric acid). ... Template:Chembox new Sulfuric (or sulphuric) acid, H2SO4, is a strong mineral acid. ... R-phrases , S-phrases , , Flash point Non-flammable. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... A nanometre (American spelling: nanometer, symbol nm) is a unit of length in the metric system, equal to one thousand-millionth of a metre, which is the current SI base unit of length. ...


The metal form is slightly paramagnetic, meaning its magnetic dipoles align with external magnetic fields even though technetium is not normally magnetic.[5] The crystal structure of the metal is hexagonal close-packed. Pure metallic single-crystal technetium becomes a type II superconductor at 7.46 K; irregular crystals and trace impurities raise this temperature to 11.2 K for 99.9% pure technetium powder.[6] Below this temperature technetium has a very high magnetic penetration depth, the largest among the elements apart from niobium.[7] Simple Illustration of a paramagnetic probe made up from miniature magnets. ... The Earths magnetic field, which is approximately a dipole. ... Magnetic field lines shown by iron filings In physics, the space surrounding moving electric charges, changing electric fields and magnetic dipoles contains a magnetic field. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... A regular hexagon A hexagon (also known as sexagon) is a polygon with six edges and six vertices. ... Fig. ... A magnet levitating above a high-temperature superconductor, cooled with liquid nitrogen. ... For other uses, see Kelvin (disambiguation). ... Superconductivity is a phenomenon occurring in certain materials at low temperatures, characterised by the complete absence of electrical resistance and the damping of the interior magnetic field (the Meissner effect. ... General Name, Symbol, Number niobium, Nb, 41 Chemical series transition metals Group, Period, Block 5, 5, d Appearance gray metallic Standard atomic weight 92. ...


Technetium is produced in quantity by nuclear fission, and spreads more readily than many radionuclides. In spite of the importance of understanding its toxicity in animals and humans, experimental evidence is scant. It appears to have low chemical toxicity. Its radiological toxicity (per unit of mass) is a function of compound, type of radiation for the isotope in question, and the isotope half-life. Technetium-99m is particularly attractive for medical applications, as the radiation from this isotope is a gamma ray with the same wavelength as X-rays used for common medical diagnostic X-ray applications, giving it adequate penetration while causing minimal damage for a gamma photon. This, plus the extremely short half-life of this metastable nuclear isomer, followed by the relatively long half-life of the daughter isotope Tc-99 which allows it to be eliminated from the body before it decays. This leads to a relatively low dose of administered radiation in biologically dose-equivalent amounts (sieverts) for a typical Tc-99m based nuclear scan (see more on this subject below).[6] Technetium-99m is a metastable nuclear isomer of technetium-99, symbolized as 99mTc. ... A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... The sievert (symbol: Sv) is the SI derived unit of dose equivalent. ...


All isotopes of technetium must be handled carefully. The most common isotope, technetium-99, is a weak beta emitter; such radiation is stopped by the walls of laboratory glassware. Soft X-rays are emitted when the beta particles are stopped, but as long as the body is kept more than 30 cm away these should pose no problem. The primary hazard when working with technetium is inhalation of dust; such radioactive contamination in the lungs can pose a significant cancer risk. For most work, careful handling in a fume hood is sufficient; a glove box is not needed.[6] In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... The radiation warning symbol (trefoil). ... A common modern fume hood. ... A glove compartment is a compartment built into the dashboard on the passengers side of an automobile, often used for miscellaneous storage. ...


Applications

Nuclear medicine

99mTc ("m" indicates that this is a metastable nuclear isomer) is used in radioactive isotope medical tests, for example as a radioactive tracer that medical equipment can detect in the body.[8] It is well suited to the role because it emits readily detectable 140 keV gamma rays, and its half-life is 6.01 hours (meaning that about fifteen sixteenths of it decays to 99Tc in 24 hours).[9] Klaus Schwochau's book Technetium lists 31 radiopharmaceuticals based on 99mTc for imaging and functional studies of the brain, myocardium, thyroid, lungs, liver, gallbladder, kidneys, skeleton, blood and tumors.[6] A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... Shown above is the bone scintigraphy of a young woman. ... A radioactive tracer is a substance containing a radioactive isotope (radioisotope). ... The electronvolt (symbol eV) is a unit of energy. ... This article is about electromagnetic radiation. ... A radiopharmaceutical is a radioactive pharmaceutical. ... The human brain In animals, the brain (enkephalos) (Greek for in the skull), is the control center of the central nervous system, responsible for behavior. ... Myocardium is the muscular tissue of the heart. ... Human respiratory system The lungs flank the heart and great vessels in the chest cavity. ... For the bird, see Liver bird. ... The gallbladder (or cholecyst, sometimes gall bladder) is a pear-shaped organ that stores about 50 ml of bile (or gall) until the body needs it for digestion. ... The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. ... For other uses, see Skeleton (disambiguation). ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... For malignant tumors specifically, see cancer. ...


Immunoscintigraphy incorporates 99mTc into a monoclonal antibody, an immune system protein capable of binding to cancer cells. A few hours after injection, medical equipment is used to detect the gamma rays emitted by the 99mTc; higher concentrations indicate where the tumor is. This technique is particularly useful for detecting hard-to-find cancers, such as those affecting the intestine. These modified antibodies are sold by the German company Hoechst (now part of Sanofi-Aventis) under the name "Scintium".[10] Monoclonal antibodies (mAb) are antibodies that are identical because they were produced by one type of immune cell, all clones of a single parent cell. ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... In anatomy, the intestine is the segment of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. ... Hoechst AG was a German life-sciences company that became Aventis after its merger with Rhône-Poulenc S.A. in 1999. ... Sanofi-aventis (Euronext: SAN, NYSE: SNY), headquartered in Paris, France, is one of the 3 largest pharmaceutical companies in the world, along with Pfizer,GlaxoSmithKline. ...


When 99mTc is combined with a tin compound it binds to red blood cells and can therefore be used to map circulatory system disorders. It is commonly used to detect gastrointestinal bleeding sites. A pyrophosphate ion with 99mTc adheres to calcium deposits in damaged heart muscle, making it useful to gauge damage after a heart attack.[11] The sulfur colloid of 99mTc is scavenged by the spleen, making it possible to image the structure of the spleen.[12] This article is about the metallic chemical element. ... “Red cell” redirects here. ... For transport in plants, see Vascular tissue. ... A phosphate, in inorganic chemistry, is a salt of phosphoric acid. ... For other uses, see Calcium (disambiguation). ... The heart and lungs, from an older edition of Grays Anatomy. ... Acute myocardial infarction (AMI or MI), more commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ... This article is about the chemical element. ... The spleen is an organ located in the abdomen, where it functions in the destruction of old red blood cells and holding a reservoir of blood. ...


Radiation exposure due to diagnostic treatment involving Tc-99m can be kept low. Because 99mTc has a short half-life and high energy gamma (allowing small amounts to be easily detected), its quick decay into the far-less radioactive 99Tc results in relatively less total radiation dose to the patient, per unit of initial activity after administration. In the form administered in these medical tests (usually pertechnetate) both isotopes are quickly eliminated from the body, generally within a few days.[11] The radiation warning symbol (trefoil). ...


Technetium for nuclear medicine purposes is usually extracted from technetium-99m generators. 95mTc, with a half-life of 61 days, is used as a radioactive tracer to study the movement of technetium in the environment and in plant and animal systems.[6] The first technetium cow (a device for separating Tc-99m from its parent isotope, Mo-99) at Brookhaven National Laboratory. ... A radioactive tracer is a substance containing a radioactive isotope (radioisotope). ...


Industrial

Technetium-99 decays almost entirely by beta decay, emitting beta particles with consistent low energies and no accompanying gamma rays. Moreover, its long half-life means that this emission decreases very slowly with time. It can also be extracted to a high chemical and isotopic purity from radioactive waste. For these reasons, it is a NIST standard beta emitter, used for equipment calibration.[6] In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... This article is about electromagnetic radiation. ... NIST logo The National Institute of Standards and Technology (NIST, formerly known as The National Bureau of Standards) is a non-regulatory agency of the United States Department of Commerce’s Technology Administration. ...


Technetium-99 has also been proposed for use in optoelectric and nanoscale nuclear batteries.[13] Nanotechnology refers broadly to a field of applied science and technology whose unifying theme is the control of matter on the atomic and molecular scale, normally 1 to 100 nanometres, and the fabrication of devices within that size range. ... A radioisotope thermoelectric generator (RTG) is a simple electrical generator which obtains its power from radioactive decay. ...


Chemical

Like rhenium and palladium, technetium can serve as a catalyst. For certain reactions, for example the dehydrogenation of isopropyl alcohol, it is a far more effective catalyst than either rhenium or palladium. Of course, its radioactivity is a major problem in finding safe applications.[6] General Name, Symbol, Number rhenium, Re, 75 Chemical series transition metals Group, Period, Block 7, 6, d Appearance grayish white Standard atomic weight 186. ... For other uses, see Palladium (disambiguation). ... Hydrogenation is a chemical reaction in which unsaturated bonds between carbon atoms are reduced by attachment of a hydrogen atom to each carbon. ... Isopropyl alcohol (also isopropanol or rubbing alcohol) is a common name for propan-2-ol, a colorless, flammable chemical compound with a strong odor. ...


Under certain circumstances, a small concentration (5×10−5 mol/L) of the pertechnetate ion in water can protect iron and carbon steels from corrosion. For this reason, pertechnetate could find use as an anodic corrosion inhibitor for steel, although technetium's radioactivity poses problems for strictly chemical uses such as these. While (for example) CrO42− can also inhibit corrosion, it requires a concentration ten times as high. In one experiment, a test specimen was kept in an aqueous solution of pertechnetate for 20 years and was still uncorroded. The mechanism by which pertechnetate prevents corrosion is not well-understood, but seems to involve the reversible formation of a thin surface layer. One theory holds that the pertechnetate reacts with the steel surface to form a layer of technetium dioxide which prevents further corrosion; the same effect explains how iron powder can be used to remove pertechnetate from water. (Activated carbon can also be used for the same effect.) The effect disappears rapidly if the concentration of pertechnetate falls below the minimum concentration or if too high a concentration of other ions is added. The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... The litre or liter (see spelling differences) is a unit of volume. ... For the hazard, see corrosive. ... For other uses, see Steel (disambiguation). ... An oxide is a chemical compound containing at least one oxygen atom and other elements. ... Activated carbon Activated carbon, also called activated charcoal or activated coal, is a general term which covers carbon material mostly derived from charcoal. ...


As noted, the radioactive nature of technetium (3 MBq per liter at the concentrations required) makes this corrosion protection impractical in almost all situations. Nevertheless, corrosion protection by pertechnetate ions was proposed (but never adopted) for use in boiling water reactors.[6] The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ...


History

Search for element 43

Dmitri Mendeleev predicted technetium's properties before it was discovered.

For a number of years there was a gap in the periodic table between molybdenum (element 42) and ruthenium (element 44). Many early researchers were eager to be the first to discover and name the missing element; its location in the table suggested that it should be easier to find than other undiscovered elements. It was first thought to have been found in platinum ores in 1828. It was given the name polinium but it turned out to be impure iridium. Then in 1846 the element ilmenium was claimed to have been discovered but was determined to be impure niobium. This mistake was repeated in 1847 with the "discovery" of pelopium.[14] Dmitri Mendeleev predicted that this missing element, as part of other predictions, would be chemically similar to manganese and gave it the name ekamanganese. Image File history File links Дмитрий_Иванович_Менделеев_4. ... Image File history File links Дмитрий_Иванович_Менделеев_4. ... Portrait of Dimitri Mendeleev by Ilya Repin (Russian: , Dimitri Ivanovich Mendeleev  ) (8 February [O.S. 27 January] 1834 in Tobolsk – 2 February [O.S. 20 January] 1907 in Saint Petersburg), was a Russian chemist. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... Gottfried Wilhelm Osann Gottfried Wilhelm Osann (26 October 1797 – 9 September 1866) was a German-Russian chemist. ... This article is about the chemical element. ... General Name, Symbol, Number niobium, Nb, 41 Chemical series transition metals Group, Period, Block 5, 5, d Appearance gray metallic Standard atomic weight 92. ... Portrait of Dimitri Mendeleev by Ilya Repin (Russian: , Dimitri Ivanovich Mendeleev  ) (8 February [O.S. 27 January] 1834 in Tobolsk – 2 February [O.S. 20 January] 1907 in Saint Petersburg), was a Russian chemist. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ...


In 1877, the Russian chemist Serge Kern reported discovering the missing element in platinum ore. Kern named what he thought was the new element davyum, after the noted English chemist Sir Humphry Davy, but it was determined to be a mixture of iridium, rhodium and iron. Another candidate, lucium, followed in 1896 but it was determined to be yttrium. Then in 1908 the Japanese chemist Masataka Ogawa found evidence in the mineral thorianite which he thought indicated the presence of element 43. Ogawa named the element nipponium, after Japan (which is Nippon in Japanese). In 2004 H. K Yoshihara utilized "a record of X-ray spectrum of Ogawa's nipponium sample from thorianite [which] was contained in a photographic plate preserved by his family. The spectrum was read and indicated the absence of the element 43 and the presence of the element 75 (rhenium)."[15] General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... Sir Humphry Davy, 1st Baronet, FRS (17 December 1778 – 29 May 1829) was a British chemist and physicist. ... For other uses, see Iron (disambiguation). ... General Name, Symbol, Number yttrium, Y, 39 Chemical series transition metals Group, Period, Block 3, 5, d Appearance silvery white Standard atomic weight 88. ... Thorianite is a rare mineral, discovered by W. D. Holland, and found in the gem-gravels of Sri Lanka, where it occurs as small, heavy, black, cubic crystals, usually much water-worn. ...


German chemists Walter Noddack, Otto Berg and Ida Tacke (later Mrs. Noddack) reported the discovery of element 75 and element 43 in 1925 and named element 43 masurium (after Masuria in eastern Prussia, now in Poland, the region where Walter Noddack's family originated).[16] The group bombarded columbite with a beam of electrons and deduced element 43 was present by examining X-ray diffraction spectrograms. The wavelength of the X-rays produced is related to the atomic number by a formula derived by Henry Moseley in 1913. The team claimed to detect a faint X-ray signal at a wavelength produced by element 43. Contemporary experimenters could not replicate the discovery, and in fact it was dismissed as an error for many years.[17][18] Walter Noddack (* 17 August 1893 in Berlin, 7 December 1960 in Berlin) was a German chemist. ... Ida Noddack Tacke (25 February 1896 in Wesel - 1978) was a German chemist and physicist. ... Sailing on Lake MikoÅ‚ajki Masuria (Polish: ; German: ) is an area in northeastern Poland famous for its lakes and forests. ... For other uses, see Prussia (disambiguation). ... Ferrocolumbite, also called niobite, columbate and columbite [(Fe, Mn)(Nb, Ta)2O6] is a black mineral that is an ore of niobium and tantalum. ... For other uses, see Electron (disambiguation). ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... It has been suggested that this article or section be merged with periodogram. ... For other uses, see Wavelength (disambiguation). ... Henry Moseley at work. ...


In 1998 John T. Armstrong of the National Institute of Standards and Technology ran "computer simulations" of the 1925 experiments and obtained results quite close to those reported by the Noddack team. He claimed that this was further supported by work published by David Curtis of the Los Alamos National Laboratory measuring the (tiny) natural occurrence of technetium.[17][19] However, the Noddack's experimental results have never been reproduced, and they were unable to isolate any element 43. Debate still exists as to whether the 1925 team actually did discover element 43. NIST logo The National Institute of Standards and Technology (NIST, formerly known as The National Bureau of Standards) is a non-regulatory agency of the United States Department of Commerce’s Technology Administration. ... Los Alamos National Laboratory, aerial view from 1995. ...


Official discovery and later history

Discovery of element 43 was finally confirmed in a 1937 experiment at the University of Palermo in Sicily conducted by Carlo Perrier and Emilio Segrè. In the summer of 1936 Segrè and his wife visited the United States, first New York at Columbia University, where he had spent time the previous summer, and then Berkeley at Ernest O. Lawrence's Radiation Laboratory. He persuaded cyclotron inventor Lawrence to let him take back some discarded cyclotron parts that had become radioactive. In early 1937 Lawrence mailed him a molybdenum foil that had been part of the deflector in the cyclotron. Segrè enlisted his experienced chemist colleague Perrier to attempt to prove through comparative chemistry that the molybdenum activity was indeed Z = 43, an element not existent in nature because of its instability against nuclear decay. With considerable difficulty they finally succeeded in isolating three distinct decay periods (90, 80, and 50 days) that eventually turned out to be two isotopes, 95Tc and 97Tc, of technetium, the name given later by Perrier and Segrè to the first man-made element.[20] University of Palermo officials wanted them to name their discovery panormium, after the Latin name for Palermo, Panormus. The researchers instead named element 43 after the Greek word τεχνητός, meaning "artificial", since it was the first element to be artificially produced.[16][14] Segrè returned to Berkeley and immediately sought out Glenn T. Seaborg. They isolated the technetium-99m isotope which is now used in some 10,000,000 medical diagnostic procedures annually.[21] This article or section should be merged with Timeline of chemical element discovery The story of the discoveries of the chemical elements is presented here in chronological order. ... The University of Palermo (Italian: Università degli Studi di Palermo) is a university located in Palermo, Italy, and founded in 1806. ... Portrait of Dr. Emilio Segre Emilio Gino Segrè (February 1, 1905 - April 22, 1989) was an Italian American physicist who, with Owen Chamberlain, won the 1959 Nobel Prize in Physics for their discovery of the antiproton. ... Alma Mater Columbia University is a private university in the United States and a member of the Ivy League. ... Berkeley is a city on the east shore of San Francisco Bay in northern California, in the United States. ... Ernest Orlando Lawrence (August 8, 1901 - August 27, 1958) was an American physicist and Nobel laureate best known for his invention of the cyclotron. ... The Berkeley Lab is perched on a hill overlooking the Berkeley central campus and San Francisco Bay. ... A pair of Dee electrodes with loops of coolant pipes on their surface at the Lawrence Hall of Science. ... For other uses, see Latin (disambiguation). ... For other uses, see Palermo (disambiguation). ... Glenn Theodore Seaborg (April 19, 1912 – February 25, 1999) won the 1951 Nobel Prize in Chemistry for discoveries in the chemistry of the transuranium elements,[1] contributed to the discovery and isolation of ten elements, developed the actinide concept and was the first to propose the actinide series which led...


In 1952 astronomer Paul W. Merrill in California detected the spectral signature of technetium (in particular, light at 403.1 nm, 423.8 nm, 426.8 nm, and 429.7 nm) in light from S-type red giants.[6] These massive stars near the end of their lives were rich in this short-lived element, meaning nuclear reactions within the stars must be producing it. This evidence was used to bolster the then unproven theory that stars are where nucleosynthesis of the heavier elements occurs.[22] More recently, such observations provided evidence that elements were being formed by neutron capture in the s-process.[6] Paul Willard Merrill (August 15, 1887 – July 19, 1961) was an American astronomer whose specialty was spectroscopy. ... Official language(s) English Capital Sacramento Largest city Los Angeles Largest metro area Greater Los Angeles Area  Ranked 3rd  - Total 158,302 sq mi (410,000 km²)  - Width 250 miles (400 km)  - Length 770 miles (1,240 km)  - % water 4. ... Extremely high resolution spectrogram of the Sun showing thousands of elemental absorption lines (fraunhofer lines) Spectroscopy is the study of the interaction between radiation (electromagnetic radiation, or light, as well as particle radiation) and matter. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giant stars. ... This article is about the astronomical object. ... In nuclear physics, a nuclear reaction is a process in which two nuclei or nuclear particles collide to produce products different from the initial particles. ... The word theory has a number of distinct meanings in different fields of knowledge, depending on their methodologies and the context of discussion. ... Nucleosynthesis is the process of creating new atomic nuclei from preexisting nucleons (protons and neutrons). ... The process of neutron capture can proceed in two ways - as a rapid process (an r-process) or a slow process (an s-process). ... This article or section does not cite its references or sources. ...


Since its discovery, there have been many searches in terrestrial materials for natural sources. In 1962, technetium-99 was isolated and identified in pitchblende from the Belgian Congo in extremely small quantities (about 0.2 ng/kg);[6] there it originates as a spontaneous fission product of uranium-238. This discovery was made by B.T. Kenna and P.K. Kuroda.[23] There is also evidence that the Oklo natural nuclear fission reactor produced significant amounts of technetium-99, which has since decayed to ruthenium-99.[6] For the band, see Pitchblende (band). ... Motto: Travail et Progres (Work and Progress) The Belgian Congo Capital Léopoldville/Leopoldstad Political structure Colony Governor  - 1908-1910 Baron Wahis  - 1946-1951 Eugène Jacques Pierre Louis Jungers  - 1958-1960 Henri Arthur Adolf Marie Christopher Cornelis History  - Established 15 November, 1908  - Congolese independence 30 June, 1960 The Belgian... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... There are two objects with this name: Unterseeboot 238 Uranium-238, the most common isotope of uranium This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Oklo is a place in the West African state of Gabon. ... Natural Reactors refer to a handful of Uranium deposits that have been discovered, mostly in Oklo, Gabon. ...


Occurrence and production

Natural production

Since technetium is unstable, only minute traces occur naturally in the Earth's crust as a spontaneous fission product of uranium. In 1999 David Curtis (see above) estimated that a kilogram of uranium contains 1 nanogram (1×10−9 g) of technetium.[24] Extraterrestrial technetium was found in some red giant stars (S-, M-, and N-types) that contain an absorption line in their spectrum indicating the presence of this element.[25] This article is about Earth as a planet. ... Fission products are the residues of fission processes. ... General Name, symbol, number uranium, U, 92 Chemical series actinides Group, period, block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ... According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giant stars. ...

Long-lived
fission products
t½(my) Yield% KeV β
99Tc .211 6.0507 294
126Sn .230 .0236 4050 γ
79Se .295 .0508 151
93Zr 1.53 6.2956 91 γ
135Cs 2.3  6.3333 269
107Pd 6.5  .1629 33
129I 15.7  .6576 194 γ

Fission products are the residues of fission processes. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... Annum is a Latin noun meaning year. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... The decay energy is the energy released by a nuclear decay. ... General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Atomic mass (98) g/mol Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... Tin-126 is a radioisotope with a halflife of 230,000 years and is one of only 7 long-lived fission products. ... 79Se is a radioisotope of selenium present in spent nuclear fuel and the wastes resulting from reprocessing this fuel. ... 93Zr is a radioisotope of zirconium with a half life of 1. ... Caesium-135 has a half-life of 2. ... Palladium-107 is a fission product with a halflife of 6. ... Iodine-129 (129I) is a radioisotope of iodine, which decays with a half-life of 16. ...

Byproduct production of Tc-99 in fission wastes

In contrast with the rare natural occurrence, bulk quantities of technetium-99 are produced each year from spent nuclear fuel rods, which contain various fission products. The fission of a gram of uranium-235 in nuclear reactors yields 27 mg of 99Tc, giving technetium a fission product yield of 6.1%.[26] Other fissile isotopes also produce similar yields of technetium,[6] e.g. 4.9% from uranium-233 or 6.21% from plutonium-239. Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant) to the point where it is no longer useful in sustaining a nuclear reaction. ... Nuclear Fuel Process A graph comparing nucleon number against binding energy Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ... Fission products are the residues of fission processes. ... Uranium-235 is an isotope of uranium that differs from the elements other common isotope, uranium-238, by its ability to cause a rapidly expanding fission chain reaction. ... Core of a small nuclear reactor used for research. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... This article or section should include material from Fissile material In nuclear engineering, a fissile material is one that is capable of sustaining a chain reaction of nuclear fission. ... Uranium-233 is a fissile artificial isotope of uranium, which is proposed as a nuclear fuel. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ...


It is estimated that up to 1994, about 49,000 TBq (78 metric tons) of technetium was produced in nuclear reactors, which is by far the dominant source of terrestrial technetium.[27] However, only a fraction of the production is used commercially. As of 2005, technetium-99 is available to holders of an ORNL permit for US$83/g plus packing charges.[28] The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second. ... A tonne or metric ton (symbol t), sometimes referred to as a metric tonne, is a measurement of mass equal to 1,000 kilograms. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... A combination of federal, state and private funds is providing $300 million for the construction of 13 facilities on ORNLs new main campus. ... USD redirects here. ...


Since the yield of technetium-99 as a product of the nuclear fission of both uranium-235 and plutonium-239 is moderate, it is present in radioactive waste of fission reactors and is produced when a fission bomb is detonated. The amount of artificially produced technetium in the environment exceeds its natural occurrence to a large extent. This is due to release by atmospheric nuclear testing along with the disposal and processing of high-level radioactive waste. Due to its high fission yield and relatively high half-life, technetium-99 is one of the main components of nuclear waste. Its decay, measured in becquerels per amount of spent fuel, is dominant at about 104 to 106 years after the creation of the nuclear waste.[27] An induced nuclear fission event. ... General Name, symbol, number uranium, U, 92 Chemical series actinides Group, period, block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight (244) g·mol−1 Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... Radioactive wastes are waste types containing radioactive chemical elements that do not have a practical purpose. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 kilometers (11 mi) above the hypocenter A nuclear weapon derives its destructive force from nuclear reactions of fusion or fission. ... Preparation for an underground nuclear test at the Nevada Test Site in the 1980s. ... Radioactive wastes are waste types containing radioactive chemical elements that do not have a practical purpose. ...


An estimated 160 TBq (about 250 kg) of technetium-99 was released into the environment up to 1994 by atmospheric nuclear tests.[27] The amount of technetium-99 from nuclear reactors released into the environment up to 1986 is estimated to be on the order of 1000 TBq (about 1600 kg), primarily by nuclear fuel reprocessing; most of this was discharged into the sea. In recent years, reprocessing methods have improved to reduce emissions, but as of 2005 the primary release of technetium-99 into the environment is by the Sellafield plant, which released an estimated 550 TBq (about 900 kg) from 1995–1999 into the Irish Sea. From 2000 onwards the amount has been limited by regulation to 90 TBq (about 140 kg) per year.[29] The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second. ... Nuclear reprocessing separates any usable nuclear fuels (e. ... 2005 is a common year starting on Saturday of the Gregorian calendar. ... The Sellafield facility on the Cumbrian coast, United Kingdom Sellafield is the name of a nuclear site, close to the village and railway station of Seascale, operated by Sellafield Ltd, but owned since 1 April 2005 by the Nuclear Decommissioning Authority. ... Relief map of the Irish Sea. ...


As a result of nuclear fuel reprocessing, technetium has been discharged into the sea in a number of locations, and some seafood contains tiny but measurable quantities. For example, lobster from west Cumbria contains small amounts of technetium.[30] The anaerobic, spore-forming bacteria in the Clostridium genus are able to reduce Tc(VII) to Tc(IV). Clostridia bacteria play a role in reducing iron, manganese and uranium, thereby affecting these elements' solubility in soil and sediments. Their ability to reduce technetium may determine a large part of Tc's mobility in industrial wastes and other subsurface environments.[31] Binomial name Homarus gammarus (Linnaeus, 1758) The European Lobster (Homarus gammarus) is a lobster whose range includes the eastern Atlantic Ocean from the Lofoten Islands in northwestern Norway to the Azores and Morocco. ... Cumbria (IPA: ), is a shire county in the extreme North West of England. ... Aerobic and anaerobic bacteria can be identified by growning them in liquid culture: 1: Obligate aerobic bacteria gather at the top of the test tube in order to absorb maximal amount of oxygen. ... An endospore is a dormant, tough, non-reproductive structure produced by a small number of bacteria from the Firmicute family. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Species Clostridium acetobutylicum Clostridium aerotolerans Clostridium botulinum Clostridium colicanis Clostridium difficile Clostridium formicaceticum Clostridium novyi Clostridium perfringens Clostridium sordelli Clostridium tetani Clostridium piliforme Clostridium tyrobutyricum etc. ... For other uses, see Genus (disambiguation). ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... General Name, symbol, number uranium, U, 92 Chemical series actinides Group, period, block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ...


The long half-life of technetium-99 and its ability to form an anionic species makes it (along with 129I) a major concern when considering long-term disposal of high-level radioactive waste. In addition, many of the processes designed to remove fission products from medium-active process streams in reprocessing plants are designed to remove cationic species like caesium (e.g., 137Cs) and strontium (e.g., 90Sr). Hence the pertechnetate is able to escape through these treatment processes. Current disposal options favor burial in geologically stable rock. The primary danger with such a course is that the waste is likely to come into contact with water, which could leach radioactive contamination into the environment. The anionic pertechnetate and iodide are less able to absorb onto the surfaces of minerals so they are likely to be more mobile. In chemistry, an anionic species is one that contains a full negative charge. ... Iodine-129 (129I) is a radioisotope of iodine, which decays with a half-life of 16. ... In chemistry, a cationic species is one that contains a full positive charge. ... General Name, Symbol, Number caesium, Cs, 55 Chemical series alkali metals Group, Period, Block 1, 6, s Appearance silvery gold Standard atomic weight 132. ... Caesium-137 is a radioactive isotope which is formed mainly by nuclear fission. ... General Name, Symbol, Number strontium, Sr, 38 Chemical series alkaline earth metals Group, Period, Block 2, 5, s Appearance silvery white metallic Standard atomic weight 87. ... General Name, Symbol, Number Strontium, Sr, 38 Series Alkaline earth metal Group, Period, Block 2 (IIA), 5, s Density, Hardness 2630 kg/m3, 1. ... The deep geological repository concept involves the encapsulation of used nuclear fuel in long-lived engineered casks which are then placed and sealed within excavated rooms in a naturally occurring geological formation at a design depth of 500 to 1000 metres below ground surface. ... An iodide ion is an iodine atom with a −1 (negative one) charge. ...


By comparison plutonium, uranium, and caesium are much more able to bind to soil particles. For this reason, the environmental chemistry of technetium is an active area of research. An alternative disposal method, transmutation, has been demonstrated at CERN for technetium-99. This transmutation process is one in which the technetium (99Tc as a metal target) is bombarded with neutrons to form the shortlived 100Tc (half life = 16 seconds) which decays by beta decay to ruthenium (100Ru). If recovery of usable ruthenium is a goal, an extremely pure technetium target is needed; if small traces of the minor actinides such as americium and curium are present in the target, they are likely to undergo fission and form more fission products which increase the radioactivity of the irradiated target. The formation of 106Ru (half life 374 days) from the fresh fission is likely to increase the activity of the final ruthenium metal, which will then require a longer cooling time after irradiation before the ruthenium can be used. General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight (244) g·mol−1 Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... General Name, symbol, number uranium, U, 92 Chemical series actinides Group, period, block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ... General Name, Symbol, Number caesium, Cs, 55 Chemical series alkali metals Group, Period, Block 1, 6, s Appearance silvery gold Standard atomic weight 132. ... // Transmutation is the conversion of one object into another. ... CERN logo The European Organization for Nuclear Research (French: ), commonly known as CERN (see Naming), pronounced (or in French), is the worlds largest particle physics laboratory, situated just northwest of Geneva on the border between France and Switzerland. ... This article is about metallic materials. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 940 MeV/c² (1. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ... The minor actinides are the actinide elements in spent fuel other than uranium and plutonium, these are termed major actinides. ... General Name, Symbol, Number americium, Am, 95 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass (243) g/mol Electron configuration [Rn] 5f7 7s2 Electrons per shell 2, 8, 18, 32, 25, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number curium, Cm, 96 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery Atomic mass (247) g/mol Electron configuration [Rn] 5f7 6d1 7s2 Electrons per shell 2, 8, 18, 32, 25, 9, 2 Physical properties Phase solid Density (near r. ... Fission products are the residues of fission processes. ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ...


The actual production of technetium-99 from spent nuclear fuel is a long process. During fuel reprocessing, it appears in the waste liquid, which is highly radioactive. After sitting for several years, the radioactivity has fallen to a point where extraction of the long-lived isotopes, including technetium-99, becomes feasible. Several chemical extraction processes are used yielding technetium-99 metal of high purity.[6]


Neutron activation of molybdenum or other pure elements

The meta stable (a state where the nucleus is in an excited state) isotope 99mTc is produced as a fission product from the fission of uranium or plutonium in nuclear reactors. Due to the fact that used fuel is allowed to stand for several years before reprocessing, all 99Mo and 99mTc will have decayed by the time that the fission products are separated from the major actinides in conventional nuclear reprocessing. The PUREX raffinate will contain a high concentration of technetium as TcO4- but almost all of this will be 99Tc. The vast majority of the 99mTc used in medical work is formed from 99Mo which is formed by the neutron activation of 98Mo. 99Mo has a half-life of 67 hours, so short-lived 99mTc (half-life: 6 hours), which results from its decay, is being constantly produced.[32] The hospital then chemically extracts the technetium from the solution by using a technetium-99m generator ("technetium cow," also occasionally called a molybdenum cow). A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... Fission products are the residues of fission processes. ... General Name, symbol, number uranium, U, 92 Chemical series actinides Group, period, block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight (244) g·mol−1 Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... Core of a small nuclear reactor used for research. ... The term major Actinides refers to the plutonium and uranium present in used nuclear fuel. ... Raffinate is a term in solvent extraction to describe a liquid stream which remains after the extraction with the immisible liquid to remove solutes from the original liquor. ... This article or section does not adequately cite its references or sources. ... The first technetium cow (a device for separating Tc-99m from its parent isotope, Mo-99) at Brookhaven National Laboratory. ...


The normal technetium cow is an alumina column which contains molybdenum-98; inasmuch as aluminium has a small neutron cross section, it is convenient for an alumina column bearing inactive 98Mo to be irradiated with neutrons to make the radioactive Mo-99 column for the technetium cow.[33] By working in this way, there is no need for the complex chemical steps which would be required to separate molybdenum from a fission product mixture. This alternative method requires that an enriched uranium target be irradiated with neutrons to form 99Mo as a fission product, then separated.[34] Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... General Name, symbol, number uranium, U, 92 Chemical series actinides Group, period, block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 940 MeV/c² (1. ... Fission products are the residues of fission processes. ...


Other technetium isotopes are not produced in significant quantities by fission; when needed, they are manufactured by neutron irradiation of parent isotopes (for example, 97Tc can be made by neutron irradiation of 96Ru).


Isotopes

Technetium is one of the two elements in the first 82 that have no stable isotopes (in fact, it is the lowest-numbered element that is exclusively radioactive); the other such element is promethium.[35] The most stable radioisotopes are 98Tc (half-life of 4.2 Ma), 97Tc (half-life: 2.6 Ma) and 99Tc (half-life: 211.1 ka).[36] Technetium (Tc) Has no stable isotopes. ... For other uses, see Isotope (disambiguation). ... General Name, Symbol, Number promethium, Pm, 61 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance metallic Atomic mass [145](0) g/mol Electron configuration [Xe] 4f5 6s2 Electrons per shell 2, 8, 18, 23, 8, 2 Physical properties Phase solid Density (near r. ... A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created radiation particle within the nucleus, or else to an atomic electron (see internal conversion) . The radionuclide, in this process, undergoes radioactive decay... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... Annum is a Latin noun meaning year. ... Annum is a Latin noun meaning year. ...


Twenty-two other radioisotopes have been characterized with atomic masses ranging from 87.933 u (88Tc) to 112.931 u (113Tc). Most of these have half-lives that are less than an hour; the exceptions are 93Tc (half-life: 2.75 hours), 94Tc (half-life: 4.883 hours), 95Tc (half-life: 20 hours), and 96Tc (half-life: 4.28 days).[36] The atomic mass (ma) is the mass of an atom at rest, most often expressed in unified atomic mass units. ... The unified atomic mass unit (u), or dalton (Da), is a small unit of mass used to express atomic and molecular masses. ...


Technetium also has numerous meta states. 97mTc is the most stable, with a half-life of 90.1 days (0.097 MeV). This is followed by 95mTc (half life: 61 days, 0.038 MeV), and 99mTc (half-life: 6.01 hours, 0.143 MeV). 99mTc only emits gamma rays, subsequently decaying to 99Tc.[36] A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... This article is about electromagnetic radiation. ...


For isotopes lighter than the most stable isotope, 98Tc, the primary decay mode is electron capture, giving molybdenum. For the heavier isotopes, the primary mode is beta emission, giving ruthenium, with the exception that 100Tc can decay both by beta emission and electron capture.[36][37] In physics, the decay mode describes a particular way a particle decays. ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ...


Technetium-99 is the most common and most readily available isotope, as it is a major product of the fission of uranium-235. One gram of 99Tc produces 6.2×108 disintegrations a second (that is, 0.62 GBq/g).[38] The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second. ...


Stability of technetium isotopes

Technetium and promethium are unusual light elements in that they have no stable isotopes. The reason for this is somewhat complicated. [39] General Name, Symbol, Number promethium, Pm, 61 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance metallic Atomic mass [145](0) g/mol Electron configuration [Xe] 4f5 6s2 Electrons per shell 2, 8, 18, 23, 8, 2 Physical properties Phase solid Density (near r. ...


Using the liquid drop model for atomic nuclei, one can derive a semiempirical formula for the binding energy of a nucleus. This formula predicts a "valley of beta stability" along which nuclides do not undergo beta decay. Nuclides that lie "up the walls" of the valley tend to decay by beta decay towards the center (by emitting an electron, emitting a positron, or capturing an electron). The liquid drop model is a model in nuclear physics which treats the nucleus as a drop of incompressible nuclear fluid, first proposed by George Gamow. ... A nuclide (from lat. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ...


For a fixed odd number of nucleons A, the graph of binding energies vs. atomic number (number of protons) is shaped like a parabola (U-shaped), with the most stable nuclide at the bottom. A single beta decay or electron captures then transforms one nuclide of mass A into the next or preceding one, if the product has a lower binding energy and the difference in energy is sufficient to drive the decay mode. When there is only one parabola, there can be only one stable isotope lying on that parabola. [citation needed] See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... A parabola A graph showing the reflective property, the directrix (light blue), and the lines connecting the focus and directrix to the parabola (blue) In mathematics, the parabola (from the Greek: παραβολή) (IPA pronunciation: ) is a conic section generated by the intersection of a right circular conical surface and a plane...


For a fixed even number of nucleons A, the graph is jagged and is better visualized as two separate parabolas for even and odd atomic numbers, because isotopes with an even number of protons and an even number of neutrons are more stable than isotopes with an odd number of neutrons and an odd number of protons. A parabola A graph showing the reflective property, the directrix (light blue), and the lines connecting the focus and directrix to the parabola (blue) In mathematics, the parabola (from the Greek: παραβολή) (IPA pronunciation: ) is a conic section generated by the intersection of a right circular conical surface and a plane...


When there are two parabolas, that is, when the number of nucleons is even, it can happen (rarely) that there is a stable nucleus with an odd number of neutrons and an odd number of protons (although there are only 4 truly stable examples as opposed to very long-lived: the light nuclei: ²H, 6Li, 10B, 14N). However, if this happens, there can be no stable isotope with an even number of neutrons and an even number of protons.[citation needed] In physics a nucleon is a collective name for two baryons: the neutron and the proton. ...


For technetium (Z=43), the valley of beta stability is centered at around 98 nucleons. However, for every number of nucleons from 95 to 102, there is already at least one stable nuclide of either molybdenum (Z=42) or ruthenium (Z=44).[citation needed] For the isotopes with odd numbers of nucleons, this immediately rules out a stable isotope of technetium, since there can be only one stable nuclide with a fixed odd number of nucleons. For the isotopes with an even number of nucleons, since technetium has an odd number of protons, any isotope must also have an odd number of neutrons. In such a case, the presence of a stable nuclide having the same number of nucleons and an even number of protons rules out the possibility of a stable nucleus.[40]


References

Works cited

Prose
  • The Encyclopedia of the Chemical Elements, edited by Cifford A. Hampel, "Technetium" entry by S. J. Rimshaw (New York; Reinhold Book Corporation; 1968; pages 689–693) Library of Congress Catalog Card Number: 68–29938
  • Nature's Building Blocks: An A-Z Guide to the Elements, by John Emsley (New York; Oxford University Press; 2001; pages 422–425) ISBN 0-19-850340-7
  • The radiochemical Manual, 2nd Ed, edited by B.J. Wilson, 1966.
  • Los Alamos National Laboratory – Technetium (viewed 1 December 2002 and 22 April 2005)
  • WebElements.com "Technetium" Uses (viewed 1 December 2002 and 22 April 2005)
  • EnvironmentalChemistry.com Nuclides / Isotopes (viewed 1 December 2002 and 22 April 2005. JavaScript required, browser-restricted access)
  • Elentymolgy and Elements Multidict by Peter van der Krogt, "Technetium" (viewed 30 April 2005; Last updated 10 April 2005 )
  • History of the Origin of the Chemical Elements and Their Discoverers by Norman E. Holden (viewed 30 April 2005; last updated 12 March 2004)
  • Technetium as a Material for AC Superconductivity Applications by S. H. Autler, Proceedings of the 1968 Summer Study on Superconducting Devices and Accelerators
  • Technetium heart scan, Dr. Joseph F. Smith Medical library (viewed 23 April 2005)
  • Gut transfer and doses from environmental technetium, J D Harrison et al 2001 J. Radiol. Prot. 21 9–11, Invited Editorial
  • Ida Tacke and the warfare behind the discovery of fission, by Kevin A. Nies (viewed 23 April 2005)
  • TECHNETIUM by John T. Armstrong (viewed 23 April 2005)
  • Technetium-99 Behaviour in the Terrestrial Environment - Field Observations and Radiotracer Experiments, Keiko Tagami, Journal of Nuclear and Radiochemical Sciences, Vol. 4, No.1, pp. A1-A8, 2003
  • Type 2 superconductors (viewed 23 April 2005)
  • The CRC Handbook of Chemistry and Physics, 85th edition, 2004–2005, CRC Press
  • K. Yoshihara, "Technetium in the Environment" in "Topics in Current Chemistry: Technetium and Rhenium", vol. 176, K. Yoshihara and T. Omori (eds.), Springer-Verlag, Berlin Heidelberg, 1996.
  • Schwochau, Klaus, Technetium, Wiley-VCH (2000), ISBN 3-527-29496-1
  • RADIOCHEMISTRY and NUCLEAR CHEMISTRY, Gregory Choppin, Jan-Olov Liljenzin, and Jan Rydberg, 3rd Edition, 2002, the chapter on nuclear stability (pdf) (viewed 5 January 2007)
Table

is the 335th day of the year (336th in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ... is the 112th day of the year (113th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 335th day of the year (336th in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ... is the 112th day of the year (113th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 335th day of the year (336th in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ... is the 112th day of the year (113th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 120th day of the year (121st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 100th day of the year (101st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 120th day of the year (121st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 71st day of the year (72nd in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... is the 113th day of the year (114th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 113th day of the year (114th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 113th day of the year (114th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 113th day of the year (114th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 335th day of the year (336th in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ...

Notes

  1. ^ LANL Periodic Table, "Technetium" paragraph 3
  2. ^ The Encyclopedia of the Chemical Elements, page 691, "Chemical Properties", paragraph 1
  3. ^ The Encyclopedia of the Chemical Elements, page 692, "Analytical Methods of Determination", paragraph 1
  4. ^ The CRC Handbook, 85th edition, Line Spectra of the Elements
  5. ^ The Encyclopedia of the Chemical Elements, page 691, paragraph 1
  6. ^ a b c d e f g h i j k l m n Schwochau, Technetium
  7. ^ Technetium as a Material for AC Superconductivity Applications
  8. ^ Reference for whole 99mTc medical use discussion except where specific cites are given: Nature's Building Blocks, page 423, "Medical Element", paragraphs 2–4
  9. ^ The Encyclopedia of the Chemical Elements, page 693, "Applications", paragraph 3 and Guide to the Elements, page 123, paragraph 3
  10. ^ Nature's Building Blocks, page 423, "Medical Element", paragraph 2
  11. ^ a b Technetium heart scan
  12. ^ The Encyclopedia of the Chemical Elements, page 693, "Applications", paragraph 3
  13. ^ University Research Program in Robotics REPORT, University of Florida, 2006-11-30, <http://www.osti.gov/bridge/servlets/purl/895620-n4Nt3U/895620.PDF>. Retrieved on 2007-10-12
  14. ^ a b History of the Origin of the Chemical Elements and Their Discoverers, Individual Element Names and History, "Technetium"
  15. ^ YOSHIHARA, H. K. (2004). "Discovery of a new element 'nipponium': re-evaluation of pioneering works of Masataka Ogawa and his son Eijiro Ogawa". Atomic spectroscopy (Spectrochim. acta, Part B) vol. 59 (no8): pp. 1305-1310. Retrieved on 2007-03-31. 
  16. ^ a b Elentymolgy and Elements Multidict, "Technetium"
  17. ^ a b Armstrong, John T. (2003). Technetium. Chemical & Engineering News.
  18. ^ Nies, Kevin A. "Ida Tacke and the warfare behind the discovery of fission" (2001).
  19. ^ Using first-principles X-ray-emission spectral-generation algorithms developed at NIST, I simulated the X-ray spectra that would be expected for Van Assche's initial estimates of the Noddacks' residue compositions. The first results were surprisingly close to their published spectrum! Over the next couple of years, we refined our reconstruction of their analytical methods and performed more sophisticated simulations. The agreement between simulated and reported spectra improved further. Our calculation of the amount of element 43 required to produce their spectrum is quite similar to the direct measurements of natural technetium abundance in uranium ore published in 1999 by Dave Curtis and colleagues at Los Alamos. We can find no other plausible explanation for the Noddacks' data than that they did indeed detect fission "masurium.#Armstrong, John T. "Technetium" Chemical & Engineering News (2003).
  20. ^ Nature's Building Blocks, page 424, paragraph 2 and LANL Periodic Table, "Technetium", paragraph 1
  21. ^ (2000) THE TRANSURANIUM PEOPLE The Inside Story. Chapter 1.2: Early Days at the Berkeley Radiation Laboratory: University of California, Berkeley & Lawrence Berkeley National Laboratory, pp.15. ISBN ISBN 1-86094-087-0. 
  22. ^ Nature's Building Blocks, page 422, "Cosmic Element", paragraph 1
  23. ^ LANL Periodic Table, "Technetium"
  24. ^ Nature's Building Blocks, page 423, "Element of History", paragraph 2
  25. ^ LANL Periodic Table, "Technetium" paragraph 1
  26. ^ Encyclopedia of the Chemical Elements, page 690, "Sources of Technetium", paragraph 1
  27. ^ a b c Topics in current chemistry, vol 176, "Technetium in the environment"
  28. ^ The CRC Handbook of Chemistry and Physics, 85th edition, The Elements
  29. ^ Technetium-99 behaviour in the terrestrial environment
  30. ^ Gut transfer and doses from environmental technetium
  31. ^ Arokiasamy J. Francis, Cleveland J. Dodge, G. E. Meinken. "Biotransformation of pertechnetate by Clostridia" Radiochimica Acta 90 09–11 (2002): 791.
  32. ^ Nature's Building Blocks, page 423, paragraph 2
  33. ^ The radiochemical manual
  34. ^ J. L. Snelgrove et al., "Development and Processing of LEU Targets for Mo-99 Production" (1995).
  35. ^ LANL Periodic Table, "Technetium" paragraph 2
  36. ^ a b c d EnvironmentalChemistry.com, "Technetium", Nuclides / Isotopes
  37. ^ CRC Handbook, 85th edition, table of the isotopes
  38. ^ The Encyclopedia of the Chemical Elements, page 693, "Toxicology", paragraph 2
  39. ^ http://book.nc.chalmers.se/KAPITEL/CH03NY3.PDF
  40. ^ RADIOCHEMISTRY and NUCLEAR CHEMISTRY

Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 90th day of the year (91st in leap years) in the Gregorian calendar. ...

External links

Wikimedia Commons has media related to:
Look up technetium in
Wiktionary, the free dictionary.

Image File history File links Commons-logo. ... Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 150 languages. ...


  Results from FactBites:
 
Technetium (Tc) - Chemical properties, Health and Environmental effects (753 words)
The chemistry of technetium is said to be similar to that of rhenium.
Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars.
Because technetium is produced in tonne quantities in nuclear reactors, it is adding to the planetary burden of unwanted radioactive waste.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m