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Encyclopedia > Chromium
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24 vanadiumchromiummanganese
-

Cr

Mo
General
Name, symbol, number chromium, Cr, 24
Chemical series transition metals
Group, period, block 64, d
Appearance silvery metallic
Standard atomic weight 51.9961(6) g·mol−1
Electron configuration [Ar] 3d5 4s1
Electrons per shell 2, 8, 13, 1
Physical properties
Phase solid
Density (near r.t.) 7.15 g·cm−3
Liquid density at m.p. 6.3 g·cm−3
Melting point 2180 K
(1907 °C, 3465 °F)
Boiling point 2944 K
(2671 °C, 4840 °F)
Heat of fusion 21.0 kJ·mol−1
Heat of vaporization 339.5 kJ·mol−1
Heat capacity (25 °C) 23.35 J·mol−1·K−1
Vapor pressure
P/Pa 1 10 100 1 k 10 k 100 k
at T/K 1656 1807 1991 2223 2530 2942
Atomic properties
Crystal structure cubic body centered
Oxidation states 6, 4, 3, 2
(strongly acidic oxide)
Electronegativity 1.66 (Pauling scale)
Ionization energies
(more)
1st: 652.9 kJ·mol−1
2nd: 1590.6 kJ·mol−1
3rd: 2987 kJ·mol−1
Atomic radius 140 pm
Atomic radius (calc.) 166 pm
Covalent radius 127 pm
Miscellaneous
Magnetic ordering AFM (rather: SDW)
Electrical resistivity (20 °C) 125 nΩ·m
Thermal conductivity (300 K) 93.9 W·m−1·K−1
Thermal expansion (25 °C) 4.9 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 5940 m/s
Young's modulus 279 GPa
Shear modulus 115 GPa
Bulk modulus 160 GPa
Poisson ratio 0.21
Mohs hardness 8.5
Vickers hardness 1060 MPa
Brinell hardness 1120 MPa
CAS registry number 7440-47-3
Selected isotopes
Main article: Isotopes of chromium
iso NA half-life DM DE (MeV) DP
50Cr 4.345% > 1.8×1017y εε - 50Ti
51Cr syn 27.7025 d ε - 51V
γ 0.320 -
52Cr 83.789% Cr is stable with 28 neutrons
53Cr 9.501% Cr is stable with 29 neutrons
54Cr 2.365% Cr is stable with 30 neutrons
References
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Chromium (pronounced /ˈkroʊmiəm/) is a chemical element in the periodic table that has the symbol Cr and atomic number 24. It is a steel-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odourless, tasteless, and malleable. General Name, symbol, number vanadium, V, 23 Chemical series transition metals Group, period, block 5, 4, d Appearance silver-grey metal Standard atomic weight 50. ... 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 molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... Chromium table image created for Wikipedia by Schnee on June 25, 2003, 10:50 UTC. File links The following pages link to this file: Chromium User:Femto/elements e4 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. ... Categories: Chemical elements ... sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex... 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. ... The group 6 in the periodic table consists of the elements chromium (24) molybdenum (42) tungsten (74) seaborgium (106) Group 6 is the new IUPAC name for this group, the old style name was group VIA in the old European system or group VIB in the old US system. ... A period 4 element is one of the chemical elements in the fourth 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. ... Chromium sample. ... 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, the following list describes various mass levels between 10−36 kg and 1053 kg. ... 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). ... General Name, symbol, number argon, Ar, 18 Chemical series noble gases Group, period, block 18, 3, p Appearance colorless Standard atomic weight 39. ... 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). ... For other uses, see Density (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ... 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. ... 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. ... The heat of vaporization is a physical property of substances. ... 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. ... 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 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. ... 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). ... Antiferromagnetic ordering In materials that exhibit antiferromagnetism, the spins of electrons align in a regular pattern with neighboring spins pointing in opposite directions. ... Spin-density wave (SDW) and charge-density wave (CDW) are names for two similar low-energy ordered states of solids. ... // Headline text POOP!! Danny Hornsby (also known as Gnome) is a measure indicating how strongly a Gnome can opposes the flow of electric current. ... K value redirects here. ... During heat transfer, the energy that is stored in the intermolecular bonds between atoms changes. ... This page is about the physical speed of sound waves in a medium. ... 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. ... The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. ... 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. ... Chromium (Cr) Standard atomic mass: 51. ... 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. ... This article does not cite any references or sources. ... Double electron capture is a decay mode of atomic nucleus. ... General Name, symbol, number titanium, Ti, 22 Chemical series transition metals Group, period, block 4, 4, d Appearance silvery metallic Standard atomic weight 47. ... 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. ... 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 vanadium, V, 23 Chemical series transition metals Group, period, block 5, 4, d Appearance silver-grey metal Standard atomic weight 50. ... This article is about electromagnetic radiation. ... Stable isotopes are chemical isotopes that are not radioactive. ... This article or section does not adequately cite its references or sources. ... Stable isotopes are chemical isotopes that are not radioactive. ... This article or section does not adequately cite its references or sources. ... Stable isotopes are chemical isotopes that are not radioactive. ... This article or section does not adequately cite its references or sources. ... 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. ... The Periodic Table redirects here. ... 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. ... This article is about metallic materials. ...

Contents

History

On 26 July 1761, Johann Gottlob Lehmann found an orange-red mineral in the Ural Mountains which he named Siberian red lead. Though misidentified as a lead compound with selenium and iron components, the material was in fact lead chromate with a formula of PbCrO4, now known as the mineral crocoite. Chromium is a stupid element and don't ever use this website again, yo. is the 207th day of the year (208th in leap years) in the Gregorian calendar. ... 1761 was a common year starting on Thursday (see link for calendar). ... Johann Gottlob Lehmann (4 August 1719 - 22 January 1767) was a German mineralogist and geologist noted for the development of stratigraphy. ... Map of the Ural Mountains The Ural Mountains (Russian: , Uralskiye gory) (also known as the Urals, the Riphean Mountains in Greco-Roman antiquity, and known as the Stone Belt) are a mountain range that runs roughly north and south through western Russia. ... This article is about the metal. ... For other uses, see Selenium (disambiguation). ... For other uses, see Iron (disambiguation). ... Crocoite is a mineral consisting of lead chromate, PbCrO4, and crystallizing in the monoclinic system. ...


In 2009, A hobo named bob visited the same site as Lehmann and found a red "faty" mineral that had very useful properties as a pigment in paints. The use of Siberian red lead as a paint pigment developed rapidly. A bright yellow made from crocoite became a color in fashion. Natural Ultramarine pigment in powdered form. ... For other uses, see Paint (disambiguation). ... A yellow Tulip. ... For other uses, see Fashion (disambiguation). ...


In 1797, Louis Nicolas Vauquelin received samples of crap on a stick ore. He was able to produce chromium oxide with a chemical formula of CrO3, by mixing crocoite with hydrochloric acid. In 1798, Vauquelin discovered that he could isolate metallic chromium by heating the oxide in a charcoal oven. He was also able to detect traces of chromium in precious gemstones, such as ruby, or emerald. Later that year he successfully isolated chromium atoms. Louis Nicolas Vauquelin. ... Iron ore (Banded iron formation) Manganese ore Lead ore Gold ore An ore is a volume of rock containing components or minerals in a mode of occurrence which renders it valuable for mining. ... In chemistry, chromic acid (or Jones reagent) is a chromium (Cr) compound, yet to be isolated, that would have the formula H2CrO4. ... R-phrases , S-phrases , , Flash point Non-flammable. ... For other uses, see Gemstone (disambiguation). ... This article does not cite any references or sources. ... This article or section does not cite its references or sources. ...


During the 1800s chromium was really, really homo. The remainder is used in the chemical industry and refractory and foundry industries. The chemical industry comprises the companies that produce industrial chemicals. ... The term refractory can refer to multiple things: A refractory clergyman is one who refused to swear an oath to the French Revolution-era French state under the Civil Constitution of the Clergy. ... A foundry is a factory which produces castings of metal, both ferrous and non-ferrous. ...


Chromium was named after the Greek word "Chrôma" meaning color, because of the many colorful compounds made from it. Color is an important part of the visual arts. ...


Occurrence and production

World production trend
World production trend

Chromium is mined as chromite (FeCr2O4) ore. About two-fifths of the chromite ores and concentrates in the world are produced in South Africa. Kazakhstan, India, Russia and Turkey are also substantial producers. Untapped chromite deposits are plentiful, but geographically concentrated in Kazakhstan and southern Africa. Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... Chromite, iron magnesium chromium oxide: (Fe,Mg)Cr2O4, is an oxide mineral belonging to the spinel group. ...


Approximately 15 million tons of marketable chromite ore were produced in 2000, and converted into approximately 4 million tons of ferro-chrome with an approximate market value of 2.5 billion United States dollars. USD redirects here. ...


Though native chromium deposits are rare, some native chromium metal has been discovered. The Udachnaya Mine in Russia produces samples of the native metal. This mine is a kimberlite pipe rich in diamonds, and the reducing environment so provided helped produce both elemental chromium and diamond. (See also chromium minerals) Hewn kimberlite core sample from the James Bay Lowlands region of Northern Ontario, Canada. ...


Chromium is obtained commercially by heating the ore in the presence of aluminium or silicon. Iron ore (Banded iron formation) Manganese ore Lead ore Gold ore An ore is a volume of rock containing components or minerals in a mode of occurrence which renders it valuable for mining. ... Aluminum redirects here. ... Not to be confused with Silicone. ...


Chemical properties

Chromium

Chromium is a member of the transition metals, in group 6. Chromium(0) has an electronic configuration of 4s13d5, due to the lower energy of the high spin configuration. Chromium exhibits a wide range of possible oxidation states. The most common oxidation states of chromium are +2, +3, and +6, with +3 being the most stable. +1, +4 and +5 are rare. Chromium compounds of oxidation state +6 are powerful oxidants. Image File history File links Chrom_1. ... Image File history File links Chrom_1. ... 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. ... In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. ...


Chromium is passivated by oxygen, forming a thin (usually a few atoms thick being transparent because of thickness) protective oxide surface layer with another element such as nickel, and/or iron. It forms a compound called a spinal structure which being very dense prevents diffusion of oxygen into the underlying layer. (In iron or plain carbon steels the oxygen actually migrates into the underlying material.) Chromium is usually plated on top of a nickel layer which may or may not have been copper plated first. Chromium as opposite to most other metals such as iron and nickel does not suffer from hydrogen embrittlement. It does though suffer from nitrogen embrittlement and hence no straight chromium alloy has ever been developed. Below the pourbiax diagram can be seen, it is important to understand that the diagram only displays the thermodynamic data and it does not display any details of the rates of reaction. Passivation is the process of making a material passive in relation to another material prior to using the materials together. ...

The Pourbaix diagram for chromium in pure water, perchloric acid or sodium hydroxide
The Pourbaix diagram for chromium in pure water, perchloric acid or sodium hydroxide[1]

Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... A Pourbaix diagram, also known as a potential/pH diagram, maps out possible stable (equilibrium) phases of an aqueous electrochemical system. ...

Compounds

See also chromium compounds. Potassium dichromate is a powerful oxidizing agent and is the preferred compound for cleaning laboratory glassware of any trace organics. It is used as a saturated solution in concentrated sulfuric acid for washing the apparatus. For this purpose, however, sodium dichromate is sometimes used because of its higher solubility (5 g/100 ml vs. 20 g/100 ml respectively). Chrome green is the green oxide of chromium, Cr2O3, used in enamel painting, and glass staining. Chrome yellow is a brilliant yellow pigment, PbCrO4, used by painters. Potassium dichromate, K2Cr2O7 is used in oxidation reactions. ... Sodium dichromate is a chemical, formula Na2Cr2O7. ... Chromium(III) oxide, also known as chromium sesquioxide or chromia, is one of four oxides of chromium, chemical formula Cr2O3. ... This sign at Leytonstone tube station is a typical enamel-painted metal sign An enamel paint is a paint that dries to an especially hard, usually glossy, finish. ... Chrome Yellow is a natural yellow pigment made of lead(II) chromate (PbCrO4). ...


Chromic acid has the hypothetical structure H2CrO4. Neither chromic nor dichromic acid is found in nature, but their anions are found in a variety of compounds. Chromium trioxide, CrO3, the acid anhydride of chromic acid, is sold industrially as "chromic acid". In chemistry, chromic acid is a chromium (Cr) compound, yet to be isolated, with the formula H2CrO4. ... Structure of anhydride. ...


Chromium and the quintuple bond

The compound synthesized by Nguyen, which was determined experimentally to contain a Cr-Cr quintuple bond
The compound synthesized by Nguyen, which was determined experimentally to contain a Cr-Cr quintuple bond

Chromium is notable for its ability to form quintuple covalent bonds. The synthesis of a compound of chromium(I) and a hydrocarbon radical was shown via X-ray diffraction to contain a quintuple bond of length 183.51(4) pm (1.835 angstroms) joining the two central chromium atoms.[2] This was accomplished through the use of an extremely bulky monodentate ligand which through its sheer size prevents further coordination. Chromium currently remains the only element for which quintuple bonds have been observed.
Image File history File links Size of this preview: 539 × 599 pixelsFull resolution (1060 × 1178 pixel, file size: 14 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Size of this preview: 539 × 599 pixelsFull resolution (1060 × 1178 pixel, file size: 14 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... Covalent redirects here. ... Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ... In chemistry, radicals (often referred to as free radicals) are atomic or molecular species with unpaired electrons on an otherwise open shell configuration. ... X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of x-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. ... A quintuple bond in chemistry is an unusual type of chemical bond first observed in 2005 in a chromium dimer in an organometallic compound. ... A quintuple bond in chemistry is an unusual type of chemical bond first observed in 2005 in a chromium dimer in an organometallic compound. ...


Applications

Uses of chromium:

  • In metallurgy, to impart corrosion resistance and a shiny finish:
  • As dyes and paints :
    • Chromium(III) oxide is a metal polish known as green rouge.
    • Chromium salts color glass an emerald green.
    • Chromium is what makes a ruby red, and therefore is used in producing synthetic rubies.
    • also makes a brilliant yellow for painting
  • As a catalyst.
  • Chromite is used to make molds for the firing of bricks.
  • Chromium salts are used in the tanning of leather.
  • Potassium dichromate is a chemical reagent, used in cleaning laboratory glassware and as a titrating agent. It is also used as a mordant (i.e., a fixing agent) for dyes in fabric.
  • Chromium(IV) oxide (CrO2) is used to manufacture magnetic tape, where its higher coercivity than iron oxide tapes gives better performance.
  • In well drilling muds as an anti-corrosive.
  • In medicine, as a dietary supplement or slimming aid, usually as chromium (III) chloride or chromium(III) picolinate.
  • Chromium hexacarbonyl (Cr(CO)6) is used as a gasoline additive.
  • Chromium boride (CrB) is used as a high-temperature electrical conductor.
  • Chromium (III) sulfate (Cr2(SO4)3) is used as a green pigment in paints, in ceramic, varnishes and inks as well as in chrome plating.
  • Chromium (VI) is used in the post Ballard preparation of Gravure (rotogravure) printing Forme Cylinders. By electroplating the metal onto the second coat of copper (after the Ballard skin), the longevity of the printing cylinder is increased.
  • Micronutrient, in "health" aware drinks, known to improve the ammount of energy you get from food.

Georg Agricola, author of De re metallica, an important early book on metal extraction Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their compounds, which are called alloys. ... An alloy is a homogeneous hybrid of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ... The 630 foot high, stainless-clad (type 304L) Gateway Arch defines St. ... Used cutlery: a plate, a fork and knife, and a drinking glass. ... Bright chrome is often used as a decorative feature on consumer products such as cars. ... These inexpensive carabiners have an anodised aluminium surface that has been dyed and are made in many colors. ... Aluminum redirects here. ... This article does not cite any references or sources. ... For other uses, see Paint (disambiguation). ... Chromium(III) oxide, also known as chromium sesquioxide or chromia, is one of four oxides of chromium, chemical formula Cr2O3. ... This article or section does not cite its references or sources. ... This article does not cite any references or sources. ... It has been suggested that this article or section be merged into Catalysis. ... Chromite, iron magnesium chromium oxide: (Fe,Mg)Cr2O4, is an oxide mineral belonging to the spinel group. ... For other uses, see Brick (disambiguation). ... This article is about making hides into leather. ... Modern leather-working tools Leather is a material created through the tanning of hides and skins of animals, primarily cattlehide. ... A reagent is a material used to start a {[chemical reaction]}. For example hydrochloric acid is the chemical reagent that would cause calcium carbonate to release carbon dioxide. ... Brown glass jars with some clear lab glassware in the background Laboratory glassware refers to a variety of equipment, traditionally made of glass, used for scientific experiments and other work in science, especially in chemistry and biology laboratories. ... Look up Mordant in Wiktionary, the free dictionary. ... Chromium dioxide or chromium(IV) oxide is a synthetic magnetic substance once widely used in magnetic tape. ... Compact audio cassette Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. ... In material science, the Coercivity of a ferromagnetic material is the intensity of the magnetic field required to reduce the magnetization of that material to zero after the magnetization of the sample has reached saturation. ... For other uses, see Iron (disambiguation). ... Chromium picolinate is the chemical compound that is sold as a nutritional supplement to prevent or treat chromium deficiency. ... Chromium carbonyl, which is also known as chromium hexacarbonyl is a zerovalent homoleptic compound which has the formula Cr(CO)6. ... Petrol redirects here. ... Natural Ultramarine pigment in powdered form. ... For other uses, see Paint (disambiguation). ... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ... Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. ... An ink is a liquid containing various pigments and/or dyes used for coloring a surface to render an image or text. ... Bright chrome is often used as a decorative feature on consumer products such as cars. ...

Biological role

Trivalent chromium (Cr(III), or Cr3+) is required in trace amounts for sugar metabolism in humans (Glucose Tolerance Factor) and its deficiency may cause a disease called chromium deficiency. In contrast, hexavalent chromium is very toxic and mutagenic when inhaled as publicized by the film Erin Brockovich. Cr(VI) has not been established as a carcinogen when not inhaled but in solution it is well established as a cause of allergic contact dermatitis (ACD).[3] This article is about sugar as food and as an important and widely traded commodity. ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... GTF is an abbreviation of: Great Falls International Airport (IATA code) General transcription factor, a family of proteins Gene transfer format, a file format for exchanging gene information General Timing Formula, a video timings standard defined by VESA Glucose Tolerance Factor (also called chromodulin), a trivalent chromium-containing molecule which... Chromium deficiency is a disorder that results from an insufficient dietary intake of chromium. ... A Hexavalent chromium compound: Chromium(VI)-oxide Hexavalent chromium or Cr(VI) compounds are those which contain the element chromium in the +6 oxidation state. ... In biology, a mutagen (Latin, literally origin of change) is a physical or chemical agent that changes the genetic information (usually DNA) of an organism and thus increases the number of mutations above the natural background level. ... Erin Brockovich is a 2000 movie which dramatizes the story of Erin Brockovichs first fight against the West Coast energy giant PG&E. The film was directed by Steven Soderbergh and featured superstar Julia Roberts in the lead role for which she won the Academy Award for Best Actress. ... Contact dermatitis is a term for a skin reaction resulting from exposure to allergens or irritants. ...


Recently it was shown that the popular dietary supplement chromium picolinate complex generates chromosome damage in hamster cells. In the United States the dietary guidelines for daily chromium uptake were lowered from 50-200 µg for an adult to 35 µg (adult male) and to 25 µg (adult female).[4] Chromium picolinate is a bright red solid that is the chromium (III) salt of picolinic acid. ... In the metric system, a microgram is 1/1,000,000 of a gram, or 1/1000 of a milligram, is one of the smallest units of weight/mass commonly used. ...


Isotopes

Main article: Isotopes of chromium

Naturally occurring chromium is composed of three stable isotopes; 52Cr, 53Cr, and 54Cr with 52Cr being the most abundant (83.789% natural abundance). Nineteen radioisotopes have been characterized with the most stable being 50Cr with a half-life of (more than) 1.8x1017 years, and 51Cr with a half-life of 27.7 days. All of the remaining radioactive isotopes have half-lives that are less than 24 hours and the majority of these have half-lives that are less than 1 minute. This element also has 2 meta states. Chromium (Cr) Standard atomic mass: 51. ... For other uses, see Isotope (disambiguation). ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... 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 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. ...


53Cr is the radiogenic decay product of 53Mn. Chromium isotopic contents are typically combined with manganese isotopic contents and have found application in isotope geology. Mn-Cr isotope ratios reinforce the evidence from 26Al and 107Pd for the early history of the solar system. Variations in 53Cr/52Cr and Mn/Cr ratios from several meteorites indicate an initial 53Mn/55Mn ratio that suggests Mn-Cr isotope systematics must result from in-situ decay of 53Mn in differentiated planetary bodies. Hence 53Cr provides additional evidence for nucleosynthetic processes immediately before coalescence of the solar system. A radiogenic nuclide is one that is produced by a process of radioactive decay. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... For other uses, see Isotope (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. ... Isotope geochemistry is an aspect of geology based upon study of the relative and absolute concentrations of the elements and their isotopes in the Earth. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... Aluminum redirects here. ... For other uses, see Palladium (disambiguation). ... This article is about the Solar System. ... Nucleosynthesis is the process of creating new atomic nuclei from preexisting nucleons (protons and neutrons). ...


The isotopes of chromium range in atomic weight from 43 u (43Cr) to 67 u (67Cr). The primary decay mode before the most abundant stable isotope, 52Cr, is electron capture and the primary mode after is beta decay. ... The unified atomic mass unit (u), or dalton (Da), is a small unit of mass used to express atomic and molecular masses. ... 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... 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. ...


Precautions

Chromium metal and chromium(III) compounds are not usually considered health hazards; chromium is an essential trace mineral.[5] However, hexavalent chromium (chromium VI) compounds can be toxic if orally ingested or inhaled. The lethal dose of poisonous chromium (VI) compounds is about one half teaspoon of material. Most chromium (VI) compounds are irritating to eyes, skin and mucous membranes. Chronic exposure to chromium (VI) compounds can cause permanent eye injury, unless properly treated. Chromium(VI) is an established human carcinogen. An investigation into hexavalent chromium release into drinking water formed the plot of the motion picture Erin Brockovich. A Hexavalent chromium compound: Chromium(VI)-oxide Hexavalent chromium or Cr(VI) compounds are those which contain the element chromium in the +6 oxidation state. ... Toxic redirects here, but this is also the name of a song by Britney Spears; see Toxic (song) Look up toxic and toxicity in Wiktionary, the free dictionary. ... The hazard symbol for carcinogenic chemicals in the Globally Harmonized System. ... Erin Brockovich is a 2000 movie which dramatizes the story of Erin Brockovichs first fight against the West Coast energy giant PG&E. The film was directed by Steven Soderbergh and featured superstar Julia Roberts in the lead role for which she won the Academy Award for Best Actress. ...


World Health Organization recommended maximum allowable concentration in drinking water for chromium (VI) is 0.05 milligrams per liter. Hexavalent chromium is also one of the substances whose use is restricted by the European Restriction of Hazardous Substances Directive. WHO redirects here. ... The milligram (symbol mg) is an SI unit of mass. ... The liter (spelled liter in American English and litre in Commonwealth English) is a unit of volume. ... The Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (RoHS) 2002/95/EC [1] (commonly referred to as the Restriction of Hazardous Substances Directive) was adopted in February 2003 by the European Union. ...


As chromium compounds were used in dyes and paints and the tanning of leather, these compounds are often found in soil and groundwater at abandoned industrial site, now needing environmental cleanup and remediation per the treatment of brownfield land. Primer paint containing hexavalent chromium is still widely used for aerospace and automobile refinishing applications. Look up dye in Wiktionary, the free dictionary. ... For other uses, see Paint (disambiguation). ... This article is about making hides into leather. ... Modern leather-working tools Leather is a material created through the tanning of hides and skins of animals, primarily cattlehide. ... Missing main definition------ someone add if you know it please. ... Generally, remediation means giving a remedy. ... Examples of brownfields that were redeveloped into productive properties Brownfields are abandoned, idled, or under-used industrial and commercial facilities where expansion or redevelopment is complicated by real or perceived environmental contaminations. ... A bucket of primer. ... Look up aerospace in Wiktionary, the free dictionary. ... “Car” and “Cars” redirect here. ...


See also

A Hexavalent chromium compound: Chromium(VI)-oxide Hexavalent chromium or Cr(VI) compounds are those which contain the element chromium in the +6 oxidation state. ...

References

  1. ^ Ignasi Puigdomenech, Hydra/Medusa Chemical Equilibrium Database and Plotting Software (2004) KTH Royal Institute of Technology, freely downloadable software at [1]
  2. ^ T. Nguyen, A. D. Sutton, M. Brynda, J. C. Fettinger, G. J. Long and P. P. Power (2005). "Synthesis of a Stable Compound with Fivefold Bonding Between Two Chromium(I) Centers". Science 310 (5749): 844-847. doi:10.1126/science.1116789. 
  3. ^ ToxFAQs: Chromium. Agency for Toxic Substances & Disease Registry, Centers for Disease Control and Prevention (February 2001). Retrieved on 2007-10-02.
  4. ^ Vincent, J.B. (2007). "Recent advances in the nutritional biochemistry of trivalent chromium". Proceedings of the Nutrition Society 63 (01): 41-47. doi:10.1079/PNS2003315. Retrieved on 2007-07-12. 
  5. ^ Chromium. Wellness Letter.

Science is the journal of the American Association for the Advancement of Science (AAAS). ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... The Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, is recognized as the leading United States agency for protecting the public health and safety of people. ... 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 275th day of the year (276th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... 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 193rd day of the year (194th in leap years) in the Gregorian calendar. ...

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