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Encyclopedia > Thorium
90 actiniumthoriumprotactinium
Ce

Th

(Uqn)
General
Name, Symbol, Number thorium, Th, 90
Chemical series Actinides
Group, Period, Block n/a, 7, f
Appearance silvery white
Standard atomic weight 232.03806(2) g·mol−1
Electron configuration [Rn] 6d2 7s2
Electrons per shell 2, 8, 18, 32, 18, 10, 2
Physical properties
Phase solid
Density (near r.t.) 11.7 g·cm−3
Melting point 2115 K
(1842 °C, 3348 °F)
Boiling point 5061 K
(4788 °C, 8650 °F)
Heat of fusion 13.81 kJ·mol−1
Heat of vaporization 514 kJ·mol−1
Heat capacity (25 °C) 26.230 J·mol−1·K−1
Vapor pressure
P(Pa) 1 10 100 1 k 10 k 100 k
at T(K) 2633 2907 3248 3683 4259 5055
Atomic properties
Crystal structure cubic face centered
Oxidation states 4
(weakly basic oxide)
Electronegativity 1.3 (scale Pauling)
Ionization energies
(more)
1st: 587 kJ·mol−1
2nd: 1110 kJ·mol−1
3rd: 1930 kJ·mol−1
Atomic radius 180 pm
Miscellaneous
Magnetic ordering no data
Electrical resistivity (0 °C) 147 nΩ·m
Thermal conductivity (300 K) 54.0 W·m−1·K−1
Thermal expansion (25 °C) 11.0 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 2490 m/s
Young's modulus 79 GPa
Shear modulus 31 GPa
Bulk modulus 54 GPa
Poisson ratio 0.27
Mohs hardness 3.0
Vickers hardness 350 MPa
Brinell hardness 400 MPa
CAS registry number 7440-29-1
Selected isotopes
Main article: Isotopes of thorium
iso NA half-life DM DE (MeV) DP
228Th syn 1.9116 years α 5.520 224Ra
229Th syn 7340 years α 5.168 225Ra
230Th syn 75380 years α 4.770 226Ra
231Th trace 25.5 hours β 0.39 231Pa
232Th 100% 1.405×1010 years α 4.083 228Ra
234Th trace 24.1 days β 0.27 234Pa
References

Thorium (IPA: /ˈθɔːriəm/) is a chemical element in the periodic table that has the symbol Th and atomic number 90. As a naturally occurring, slightly radioactive metal, it has been considered as an alternative nuclear fuel to uranium. General Name, Symbol, Number actinium, Ac, 89 Chemical series actinides Group, Period, Block 3, 7, f Appearance silvery Atomic mass (227) g·mol−1 Electron configuration [Rn] 6d1 7s2 Electrons per shell 2, 8, 18, 32, 18, 9, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number protactinium, Pa, 91 Chemical series actinides Group, Period, Block n/a, 7, f Appearance bright, silvery metallic luster Standard atomic weight 231. ... General Name, Symbol, Number cerium, Ce, 58 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 140. ... By Greatpatton [1] File links The following pages link to this file: Thorium User:Femto/elements e11 Categories: GFDL images ... 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. ... The actinide series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series is named after actinium. ... 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. ... 6 *Lanthanides 7 **Actinides IUPAC has not recommended a specific format for the periodic table, so different conventions are permitted and are often used for the group number of lanthanides and actinides. ... A period 7 element is one of the chemical elements in the seventh row (or period) of the periodic table of the elements. ... The f-block of the periodic table of elements consists of those elements for which, in the atomic ground state, the highest-energy electrons occupy f-orbitals. ... Color is an important part of the visual arts. ... 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 (eg, a crystal). ... General Name, Symbol, Number radon, Rn, 86 Chemical series noble gases Group, Period, Block 18, 6, p Appearance colorless Atomic mass (222) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p6 Electrons per shell 2, 8, 18, 32, 18, 8 Physical properties Phase gas Density (0 °C, 101. ... e- redirects here. ... [[Image:Valence shell 011 Sodiumup of one or more electron subshells, or sublevels, which have two or more orbitals with the same angular momentum quantum number l. ... 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). ... In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is... Room temperature describes a certain temperature within enclosed space that is uses for various purposes by human beings. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... Fahrenheit is a temperature scale named after the German-Dutch physicist Daniel Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ... Italic text This article is about the boiling point of liquids. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... Fahrenheit is a temperature scale named after the German-Dutch physicist Daniel Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ... 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. ... In chemistry and physics, 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... Acids and bases: Acid-base reaction pH Self-ionization of water Buffer solutions Systematic naming Acid-base extraction Acidity function Proton affinity Acids: Strong acids Weak acids Superacids Lewis acids Mineral acids Organic acids Bases: Strong bases Weak bases Superbases Lewis bases Organic bases edit In chemistry, a base is... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... The ionization energy (IE) of an atom or of a molecule is the energy required to strip it of an electron. ... These tables list the ionization energy in kJ/mol necessary to remove an electron from a neutral atom (first energy), respectively from a singly, doubly, etc. ... 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. ... Magnetic lines of force of a bar magnet shown by iron filings on paper In physics, magnetism is one of the phenomena by which materials exert attractive or repulsive forces on other materials. ... Electrical resistivity (also known as specific electrical resistance) is a measure of how strongly a material opposes the flow of electric current. ... In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... During heat transfer, the energy that is stored in the intermolecular bonds between atoms changes. ... Sound is a vibration that travels through an elastic medium as a wave. ... Metre per second (U.S. spelling: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector), defined by distance in metres divided by time in seconds. ... In solid mechanics, Youngs modulus (E) is a measure of the stiffness of a given material. ... In materials science, shear modulus, G, or sometimes S or μ, sometimes referred to as the modulus of rigidity, is defined as the ratio of shear stress to the shear strain:[1] where = shear stress; force acts on area ; = shear strain; length changes by amount . ... The bulk modulus (K) of a substance essentially measures the substances resistance to uniform compression. ... Figure 1: Rectangular specimen subject to compression, with Poissons ratio circa 0. ... This article or section does not cite any references or sources. ... A Vickers hardness tester The Vickers hardness test was developed in the early 1920s as an alternative method to measure the hardness of materials. ... The Brinell scale characterises the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Thorium (Th) Standard atomic mass: 232. ... Isotopes are any of the several different forms of an element each having different atomic mass (mass number). ... 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 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. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... 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. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... 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. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... A trace radioisotope is a radioisotope that is naturally occurring. ... Hours is the name of the critically acclaimed second album by Welsh rock group Funeral for a Friend. ... 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 protactinium, Pa, 91 Chemical series actinides Group, Period, Block n/a, 7, f Appearance bright, silvery metallic luster Standard atomic weight 231. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... A trace radioisotope is a radioisotope that is naturally occurring. ... A day is any of several different units of time. ... 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 protactinium, Pa, 91 Chemical series actinides Group, Period, Block n/a, 7, f Appearance bright, silvery metallic luster Standard atomic weight 231. ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... Articles with similar titles include the NATO phonetic alphabet, which has also informally been called the “International Phonetic Alphabet”. For information on how to read IPA transcriptions of English words, see IPA chart for English. ... The periodic table of the chemical elements A chemical element, or element for short, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... For a diagram of the periodic table, see standard periodic table below. ... It has been suggested that List of elements by atomic number be merged into this article or section. ... 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. ...

Contents

Notable characteristics

When pure, thorium is a silvery white metal that retains its luster for several months. However, when it is exposed to oxygen, thorium slowly tarnishes in air, becoming grey and eventually black. Thorium dioxide (ThO2), also called thoria, has the highest melting point of any oxide (3300°C)[1]. When heated in air, thorium metal turnings ignite and burn brilliantly with a white light. Thorium dioxide (ThO2), also called thorium(IV) oxide (IUPAC) is a white, crystalline powder. ... Various examples of swarf, including a block of compressed swarf Swarf (or turnings) is shavings and chippings of metal -- the debris or waste resulting from metalworking operations. ...


Thorium has the largest liquid range of any element: 2946°C (2946 K) between the melting point and boiling point.


See Actinides in the environment for details of the environmental aspects of thorium. This article about actinides in the environment is about the sources, environmental behaviour and effects of actinides in the environment. ...


Applications

Applications of thorium:

Applications of thorium dioxide (ThO2): An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resultant material has metallic properties. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Strength of materials is materials science applied to the study of engineering materials and their mechanical behavior in general (such as stress, deformation, strain and stress-strain relations). ... Block quote In materials science, creep is the term used to describe the tendency of a material to move or to deform permanently to relieve stresses. ... General Name, Symbol, Number tungsten, W, 74 Chemical series transition metals Group, Period, Block 6, 6, d Appearance grayish white, lustrous Standard atomic weight 183. ... e- redirects here. ... Thermionic emission (archaically known as the Edison effect) is the flow of electrons from a metal or metal oxide surface, caused by thermal vibrational energy overcoming the electrostatic forces holding electrons to the surface. ... Diagram of a copper cathode in a Daniells cell. ... Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. ... In metallurgy, refraction is a property of metals that indicates their ability to withstand heat. ... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ... Uranium-thorium dating, also often referred to as thorium-230 dating, uranium-series disequilibrium dating or uranium-series dating, is a radiometric dating technique commonly used to determine the age of carbonate materials such as speleothem or coral. ... FOSSIL is a standard for allowing serial communication for telecommunications programs under DOS. FOSSIL is an acronym for Fido Opus Seadog Standard Interface Layer. ... Fertile material is a term used to describe nuclides which generally themselves do not undergo induced fission (fissionable by thermal neutrons) but from which fissile material is generated by neutron absorption and subsequent nuclei conversions. ... Nuclear Fuel Process A graph compairing 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. ... In nuclear physics, an energy amplifier is a novel type of nuclear power reactor, a subcritical reactor, in which an energetic particle beam is used to stimulate a reaction, which in turn releases enough energy to power the particle accelerator and leave an energy profit for power generation. ... 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. ... Radiation protection, sometimes known as radiological protection, is the science of protecting people and the environment from the harmful effects of radiation. ... For Pb as an abbreviation, see PB. General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ... Depleted uranium storage yard. ... Core of a small nuclear reactor used for research. ... Thorium dioxide (ThO2), also called thorium(IV) oxide (IUPAC) is a white, crystalline powder. ...

  • Mantles in portable gas lights. These mantles glow with a dazzling light (unrelated to radioactivity) when heated in a gas flame.
  • Used to control the grain size of tungsten used for electric lamps.
  • Used for high-temperature laboratory crucibles.
  • Added to glass, it helps create glasses of a high refractive index and with low dispersion. Consequently, they find application in high-quality lenses for cameras and scientific instruments.
  • Has been used as a catalyst:
  • Thorium dioxide is the active ingredient of Thorotrast, which was used as part of X-ray diagnostics. This use has been abandoned due to the carcinogenic nature of Thorotrast.

For other uses of mantle see: mantle (disambiguation) An incandescent gas mantle, gas mantle, or Welsbach mantle is a device for generating bright white light when heated by a flame. ... General Name, Symbol, Number tungsten, W, 74 Chemical series transition metals Group, Period, Block 6, 6, d Appearance grayish white, lustrous Standard atomic weight 183. ... For other uses, see Crucible (disambiguation). ... Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... Dispersion of a light beam in a prism. ... A lens. ... It has been suggested that this article or section be merged into Catalysis. ... Ammonia is a compound with the formula NH3. ... 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). ... Pumpjack pumping an oil well near Lubbock, Texas Ignacy Łukasiewicz - inventor of the refining of kerosene from crude oil. ... Factory of Shukhov cracking process, Baku, USSR, 1934 In petroleum geology and chemistry, cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules (e. ... Sulfuric (or sulphuric) acid, H2SO4, is a strong mineral acid. ... Thorotrast is a suspension containing particles of the radioactive compound thorium dioxide, ThO2, used as a contrast medium in X-ray diagnostics in the 1930s and 40s (use in some countries, such as the U.S. continued into the 1950s). ... 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... In pathology, a carcinogen is any substance or agent that promotes cancer. ...

History

M. T. Esmark found a black mineral on Løvøy Island, Norway and gave a sample to Professor Jens Esmark, a noted mineralogist who was not able to identify it so he sent a sample to the Swedish chemist Jöns Jakob Berzelius for examination in 1828.[2] Berzelius analysed it and named it after Thor, the Norse god of thunder. The metal had virtually no uses until the invention of the gas mantle in 1885. Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ... Mineralogy is an earth science that involves the chemistry, crystal structure, and physical (including optical) properties of minerals. ... Friherre Jöns Jakob Berzelius (August 20, 1779 – August 7, 1848) was a Swedish chemist. ... Thors battle against the giants, by MÃ¥rten Eskil Winge, 1872 Thor (Old Norse: Þórr) is the red-haired and bearded god of thunder and war in Norse Mythology and more generally Germanic mythology (Old English: Þunor, Old Dutch and Old High German: Donar, from Proto-Germanic *Þunraz). ... Norse, Viking or Scandinavian mythology comprises the indigenous pre-Christian religion, beliefs and legends of the Scandinavian peoples, including those who settled on Iceland, where most of the written sources for Norse mythology were assembled. ... For other uses of mantle see: mantle (disambiguation) An incandescent gas mantle, gas mantle, or Welsbach mantle is a device for generating bright white light when heated by a flame. ...


The crystal bar process (or Iodide process) was discovered by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925 to produce high-purity metallic thorium. [3] The crystal bar process (or Iodide process) was discovered by Anton Eduard van Arkel and Jan Hedrik de Boer in 1925. ... Anton Eduard van Arkel, (s-Gravenzande Netherlands, November 19, 1893 – Leiden, March 14, 1976) was a Dutch chemist. ...


The name ionium was given early in the study of radioactive elements to the 230Th isotope produced in the decay chain of 238U before it was realized that ionium and thorium were chemically identical. The symbol Io was used for this supposed element. Isotopes are any of the several different forms of an element each having different atomic mass (mass number). ... Nearly all the decay products of radioactive decay are themselves radioactive. ... 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. ...


Occurrence

Monazite, a rare-earth-and-thorium-phosphate mineral, is the primary source of the world's thorium
Monazite, a rare-earth-and-thorium-phosphate mineral, is the primary source of the world's thorium

Thorium is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium, and is about as common as lead. Soil commonly contains an average of around 12 parts per million (ppm) of thorium. Thorium occurs in several minerals, the most common being the rare earth-thorium-phosphate mineral, monazite, which contains up to about 12% thorium oxide. There are substantial deposits in several countries. 232Th decays very slowly (its half-life is about three times the age of the earth) but other thorium isotopes occur in the thorium and uranium decay chains. Most of these are short-lived and hence much more radioactive than 232Th, though on a mass basis they are negligible. India is believed to have 25% of the world's Thorium reserves. [4] Monazite Thorium is a silvery radioactive, metallic element. ... Monazite Thorium is a silvery radioactive, metallic element. ... Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland Technically, soil forms the pedosphere: the interface between the lithosphere (rocky part of the planet) and the biosphere, atmosphere, and hydrosphere. ... 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. ... For Pb as an abbreviation, see PB. General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ... A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition, a highly ordered atomic structure and specific physical properties. ... Monazite powder In geology, the mineral monazite is a reddish-brown phosphate containing rare earth metals and an important source of thorium, lanthanum, and cerium. ... 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. ... Isotopes are any of the several different forms of an element each having different atomic mass (mass number). ... 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. ...


See also thorium minerals.


Distribution

Present knowledge of the distribution of Thorium resources is poor because of the relatively low-key exploration efforts arising out of insignificant demand.[5] Under the prevailing estimate, Australia and India have particularly large reserves of thorium.

  • The prevailing estimate of the economically available thorium reserves comes from the US Geological Survey, Mineral Commodity Summaries (1997-2006):[6][7]
Country Th Reserves (tonnes) Th Reserve Base (tonnes)
Australia 300,000 340,000
India 290,000 300,000
Norway 170,000 180,000
United States 160,000 300,000
Canada 100,000 100,000
South Africa 35,000 39,000
Brazil 16,000 18,000
Malaysia 4,500 4,500
Other Countries 95,000 100,000
World Total 1,200,000 1,400,000
  • Another estimate of Reasonably Assured Reserves (RAR) and Estimated Additional Reserves (EAR) of thorium comes from OECD/NEA, Nuclear Energy, "Trends in Nuclear Fuel Cycle", Paris, France (2001)[8]
Country RAR Th (tonnes) EAR Th (tonnes)
Brazil 606,000 700,000
Turkey 380,000 500,000
India 319,000 -
United States 137,000 295,000
Norway 132,000 132,000
Greenland 54,000 32,000
Canada 45,000 128,000
Australia 19,000 -
South Africa 18,000 -
Egypt 15,000 309,000
Other Countries 505,000 -
World Total 2,230,000 2,130,000

The two sources vary wildly for countries such as Brazil, Turkey, and Australia.


Thorium as a nuclear fuel

Thorium metal foil (approximately 0.5 mm thick) sealed in a glass ampoule under an argon atmosphere to prevent oxidation

Thorium, as well as uranium and plutonium, can be used as fuel in a nuclear reactor. Although not fissile itself, 232Th will absorb slow neutrons to produce uranium-233 (233U), which is fissile. Hence, like 238U, it is fertile. In one significant respect 233U is better than the other two fissile isotopes used for nuclear fuel, 235U and plutonium-239 (239Pu), because of its higher neutron yield per neutron absorbed. Given a start with some other fissile material (235U or 239Pu), a breeding cycle similar to, but more efficient than that currently possible with the 238U-to-239Pu cycle (in slow-neutron reactors), can be set up. The 232Th absorbs a neutron to become 233Th which normally decays to protactinium-233 (233Pa) and then 233U. The irradiated fuel can then be unloaded from the reactor, the 233U separated from the thorium (a relatively simple process since it involves chemical instead of isotopic separation), and fed back into another reactor as part of a closed nuclear fuel cycle. Image File history File linksMetadata Download high-resolution version (643x1158, 63 KB) Thorium metal foil (approximately 0. ... Image File history File linksMetadata Download high-resolution version (643x1158, 63 KB) Thorium metal foil (approximately 0. ... 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. ... 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. ... A thermal neutron is a free neutron with a kinetic energy level of ca. ... A thermal reactor is the most common category of nuclear reactor. ... General Name, Symbol, Number protactinium, Pa, 91 Chemical series actinides Group, Period, Block n/a, 7, f Appearance bright, silvery metallic luster Standard atomic weight 231. ... The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. ...


Problems include the high cost of fuel fabrication due partly to the high radioactivity of 233U which is a result of its contamination with traces of the short-lived 232U; the similar problems in recycling thorium due to highly radioactive 228Th; some weapons proliferation risk of 233U; and the technical problems (not yet satisfactorily solved) in reprocessing. Much development work is still required before the thorium fuel cycle can be commercialised, and the effort required seems unlikely while (or where) abundant uranium is available.


Nevertheless, the thorium fuel cycle, with its potential for breeding fuel without fast neutron reactors, holds considerable potential long-term benefits. Thorium is significantly more abundant than uranium, and is a key factor in sustainable nuclear energy. The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. ... Shevchenko BN350 nuclear fast reactor and desalination plant situated on the shore of the Caspian Sea. ...


India, having about 25% of the world's reserves [4], has planned its nuclear power program to eventually use thorium exclusively, phasing out uranium as a feed stock. This ambitious plan uses both fast and thermal breeder reactors. The Advanced Heavy Water Reactor and KAMINI reactor are efforts in this direction. A breeder reactor is a nuclear reactor that breeds fuel. ... The Advanced Heavy Water Reactor (AHWR) is a proposed heavy water moderated nuclear power reactor that will be the next generation design of the PHWR type. ... KAMINI (Kalpakkam Mini reactor) is a Uranium-233 fueled, low power (30 kW) research reactor designed and built jointly by the Bhabha Atomic Research Centre (BARC) and Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam. ...


In 2007, Norway was debating whether or not to focus on Thorium plants.


The primary fuel of the HT3R Project in Odessa, Texas, USA will be Ceramic-coated thorium beads. The High-Temperature Teaching and Test Reactor Energy Research Facility (nicknamed HT3R, pronounced appropriately heater) is a proposed $457 million massively multi-purpose energy research facility set to be located in Andrews, Texas. ... Official language(s) No official language See languages of Texas Capital Austin Largest city Houston Largest metro area Dallas–Fort Worth Metroplex Area  Ranked 2nd  - Total 261,797 sq mi (678,051 km²)  - Width 773 miles (1,244 km)  - Length 790 miles (1,270 km)  - % water 2. ...


Isotopes

Main article: isotopes of thorium

Naturally occurring thorium is composed of one isotope: 232Th. Twenty-seven radioisotopes have been characterized, with the most abundant and/or stable being 232Th with a half-life of 14.05 billion years, 230Th with a half-life of 75,380 years, 229Th with a half-life of 7340 years, and 228Th with a half-life of 1.92 years. All of the remaining radioactive isotopes have half-lives that are less than thirty days and the majority of these have half-lives that are less than ten minutes. One isotope, 229Th, has a nuclear isomer (or metastable state) with a remarkably low excitation energy of 3.5 eV. [9] Thorium (Th) Standard atomic mass: 232. ... Isotopes are any of the several different forms of an element each having different atomic mass (mass number). ... Thorium 232 is a naturally occurring isotope of thorium. ... A radionuclide is an atom with an unstable nucleus. ... 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 set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... 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 known isotopes of thorium range in atomic weight from 210 u (210Th)[10] to 236 u (236Th). ... The unified atomic mass unit (u), or Dalton (Da), is a small unit of mass used to express atomic and molecular masses. ...


Precautions

Powdered thorium metal is often pyrophoric and should be handled carefully. A pyrophoric substance is a substance that ignites spontaneously, that is, its autoignition temperature is below room temperature. ...


Natural thorium decays very slowly compared to many other radioactive materials, and the alpha radiation emitted cannot penetrate human skin. Owning and handling small amounts of thorium, such as a gas mantle, is considered safe if care is taken not to ingest the thorium -- lungs and other internal organs can be penetrated by alpha radiation. Exposure to aerosolized thorium can lead to increased risk of cancers of the lung, pancreas and blood. Exposure to thorium internally leads to increased risk of liver diseases. This element has no known biological role. See also Thorotrast. An alpha particle is deflected by a magnetic field Alpha particles or alpha rays are a form of particle radiation which are highly ionizing and have low penetration. ... For other uses of mantle see: mantle (disambiguation) An incandescent gas mantle, gas mantle, or Welsbach mantle is a device for generating bright white light when heated by a flame. ... 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). ... Human respiratory system The lungs flank the heart and great vessels in the chest cavity. ... The pancreas is a gland organ in the digestive and endocrine systems of vertebrates[2]. It is both exocrine (secreting pancreatic juice containing digestive enzymes) and endocrine (producing several important hormones, including insulin, glucagon, and somatostatin). ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... The liver is an organ present in vertebrates and some other animals. ... Thorotrast is a suspension containing particles of the radioactive compound thorium dioxide, ThO2, used as a contrast medium in X-ray diagnostics in the 1930s and 40s (use in some countries, such as the U.S. continued into the 1950s). ...


Thorium Extraction

Thorium has been extracted chiefly from monazite through a multi-stage process. In the first stage, the monazite sand is dissolved in an inorganic acid such as sulfuric acid (H2SO4). In the second, the Thorium is extracted into an organic phase containing an amine. Next it is separated or "stripped" using an anion such as nitrate, chloride, hydroxide, or carbonate, returning the thorium to an aqueous phase. Finally, the thorium is precipitated and collected.[11]


See also

David Hahn (born October 1976) attempted to build a nuclear breeder reactor in 1994 in his backyard shed in Clinton Township, Michigan, a suburb of Detroit, at the age of 17. ... For a diagram of the periodic table, see standard periodic table below. ... Core of a small nuclear reactor used for research. ... Nearly all the decay products of radioactive decay are themselves radioactive. ... On the morning of July 2, 1956, an explosion involving scrap thorium occurred at the Sylvania Electric Products Metallurgical Laboratory in Bayside, New York. ... In various fictional settings, real materials may be portrayed as having different or additional properties, particularly when interacting with the unique elements of the setting itself. ...

References

  1. ^ Emsley, John (2001). Nature's Building Blocks, (Hardcover, First Edition), Oxford University Press, page 441. ISBN 0198503407. 
  2. ^ Thorium. BBC.co. Retrieved on 2007-01-18.
  3. ^ van Arkel, A.E.; de Boer, J.H. (1925). "Preparation of pure titanium, zirconium, hafnium, and thorium metal". Zeitschrift für Anorganische und Allgemeine Chemie 148: 345-350. Retrieved on 2006-05-06. 
  4. ^ a b US approves Indian nuclear deal. BBC News (2006-12-09).
  5. ^ K.M.V. Jayaram. An Overview of World Thorium Resources, Incentives for Further Exploration and Forecast for Thorium Requirements in the Near Future.
  6. ^ U.S. Geological Survey, Mineral Commodity Summaries - Thorium.
  7. ^ Information and Issue Briefs - Thorium. World Nuclear Association. Retrieved on 2006-11-01.
  8. ^ IAEA: Thorium fuel cycle -- Potential benefits and challenges, pp 45(table 8), 97(ref 78). 
  9. ^ Phys. Rev. C 73 044326 (April 2006)
  10. ^ Phys. Rev. C 52, 113–116 (1995)
  11. ^ Crouse, David; Brown, Keith (December 1959). "The Amex Process for Extracting Thorium Ores with Alkyl Amines".Industrial & Engineering Chemistry 51 (12): 1461. Retrieved on 2007-03-09

Oxford University Press (OUP) is a highly-respected publishing house and a department of the University of Oxford in England. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 18th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday (link displays full 2006 calendar) of the Gregorian calendar. ... is the 126th day of the year (127th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday (link displays full 2006 calendar) of the Gregorian calendar. ... is the 305th day of the year (306th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 68th day of the year (69th in leap years) in the Gregorian calendar. ...

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  Results from FactBites:
 
ATSDR - ToxFAQs™: Thorium (937 words)
Thorium is used to make ceramics, gas lantern mantles, and metals used in the aerospace industry and in nuclear reactions.
Liver diseases and effects on the blood were found in people injected with thorotrast, a thorium compound injected into the body as a radiographic contrast medium between the years 1928 and 1955.
People who had large amounts of thorium injected into their blood for special x-ray tests had more than the usual number of liver tumors, cancers of the blood, such as leukemia, and tumors of the bone, kidney, spleen, and pancreas.
Thorium - Wikipedia, the free encyclopedia (1100 words)
Thorium is a chemical element in the periodic table that has the symbol Th and atomic number 90.
Thorium is used to coat tungsten wire used in electronic equipment, improving the electron emission of heated cathodes.
Thorium is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium, and is about as common as lead.
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