24 vanadium ← chromium → manganese - ↑ Cr ↓ Mo Periodic table - Extended periodic table
General
Name, symbol, number	chromium, Cr, 24
Chemical series	transition metals
Group, period, block	6, 4, 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. Vanadium (vəˈneɪdiəm is a Chemical element that has the symbol V and Atomic number 23 Manganese (ˈmæŋgəniːz is a Chemical element, designated by the symbol Mn. Molybdenum (məˈlɪbdənəm from the Greek word for the metal " Lead " is a Group 6 Chemical element with the symbol Mo This is a typical display of the periodic table of the elements and contains the symbol and Atomic number of each element Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of Chemical elements, sorted by name Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of chemical elements by symbol, including the A table of Chemical elements ordered by Atomic number and color coded according to type of element In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in In Chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings It commonly refers to any element in In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in 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 respective highest-energy electrons in each element in a block belong to the same Atomic Biological occurrences Group 6 is notable in that it contains some of the only elements in periods 5 and 6 with a known role in the biological chemistry of living organisms molybdenum A period 4 element is one of the Chemical elements in the fourth row (or period) of the periodic table of the elements. The d-block of the periodic table of the elements consists of those Periodic table groups that contain elements in which in the atomic ground state the highest-energy The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass To help compare different orders of magnitude, the following list describes various Mass levels between 10&minus36&thinsp kg and 1053&thinspkg Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other This article pertains to the chemical element For other uses see Argon (disambiguation. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An electron shell may be crudely thought of as an Orbit followed by Electrons around an Atom nucleus. 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 A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed 19 g·cm−3
Liquid density at m.p.	6. Kilogram per cubic metre is the SI measure of Density and is represented as kg/m³ where kg stands for Kilogram and m³ stands for Cubic metre The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 3 g·cm−3
Melting point	2180 K (1907 °C, 3465 °F)
Boiling point	2944 K (2671 °C, 4840 °F)
Heat of fusion	21. The melting point of a solid is the temperature range 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 The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The standard Enthalpy of fusion (symbol \Delta{}H_{fus} also known as the heat of fusion or specific melting heat, is the amount of 0 kJ·mol−1
Heat of vaporization	339. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required 5 kJ·mol−1
Specific heat capacity	(25 °C) 23. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity 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, 5 [2], 4, 3, 2, 1 (strongly acidic oxide)
Electronegativity	1. Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. The oxidation number of a central atom in a coordination compound is the charge that it would have if all the Ligands were removed along with the Electron pairs In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons 66 (Pauling scale)
Ionization energies (more)	1st: 652. The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron These tables list the Ionization energy in kJ/mol necessary to remove one mole of Electrons from one mole of neutral gaseous Atoms (first energy respectively 9 kJ·mol−1
	2nd: 1590. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material 6 kJ·mol−1
	3rd: 2987 kJ·mol−1
Atomic radius	140 pm
Atomic radius (calc. Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth )	166 pm
Covalent radius	127 pm
Miscellaneous
Magnetic ordering	AFM (rather: SDW)
Electrical resistivity	(20 °C) 125 nΩ·m
Thermal conductivity	(300 K) 93. The covalent radius, r cov is a measure of the size of Atom which forms part of a Covalent bond. In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. In materials that exhibit antiferromagnetism, the magnetic moments of atoms or molecules usuallyrelated to the spins of Electrons align in a regular pattern with neighboring Spin-density wave (SDW and charge-density wave (CDW are names for two similar low-energy ordered states of solids 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 property of a material that indicates its ability to conduct Heat. 9 W·m−1·K−1
Thermal expansion	(25 °C) 4. When the Temperature of a substance changes the energy that is stored in the Intermolecular bonds between atoms changes 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. Sound is a vibration that travels through an elastic medium as a Wave. In Solid mechanics, Young's modulus (E is a measure of the Stiffness of an isotropic elastic material In Materials science, shear modulus or modulus of rigidity, denoted by G, or sometimes S or μ, is defined as the ratio of Shear Poisson's ratio ( ν) named after Simeon Poisson, is the ratio of the relative contraction strain, or transverse strain (normal to 21
Mohs hardness	8. 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 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. The Vickers hardness test was developed in 1924 by Smith and Sandland as an alternative method to measure the Hardness of materials The Brinell scale characterizes 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 They are also referred to Naturally occurring Chromium ( Cr) is composed of three stable Isotopes 52Cr 53Cr and 54Cr with 52Cr being Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides In Chemistry, natural abundance (NA refers to the abundance Isotopes of a Chemical element as naturally found on a planet Half-Life (computer-game page here It's already listed in the disambiguation page Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The decay energy is the Energy released by a Nuclear decay. The energy difference of the Reactants is often written as Q: where Q In Nuclear physics, a decay product, also known as a daughter product, daughter isotope or daughter nuclide, is a Nuclide 345% > 1. 8×1017y εε - 50Ti 51Cr syn 27.7025 d ε - 51V γ 0. The letter Y is the twenty-fifth letter in the modern Latin alphabet. Double electron capture is a Decay mode of Atomic nucleus. For a nuclide ( A, Z) with number of Nucleons A and Atomic Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22 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 To help compare Orders of magnitude of different times this page lists times between 106 seconds and 107 seconds (approximately 11 Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the Vanadium (vəˈneɪdiəm is a Chemical element that has the symbol V and Atomic number 23 Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions 320 - 52Cr 83. 789% 52Cr is stable with 28 neutrons 53Cr 9. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 501% 53Cr is stable with 29 neutrons 54Cr 2. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 365% 54Cr is stable with 30 neutrons
References
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Chromium (pronounced /ˈkroʊmiəm/) is a chemical element which has the symbol Cr and atomic number 24. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. Recommended values for many properties of the elements together with various references are collected on these data pages A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. See also List of elements by atomic number In Chemistry and Physics, the atomic number (also known as the proton It is a steel-gray, lustrous, hard metal that takes a high polish and has a high melting point. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across It is also odourless, tasteless, and malleable.

History

On 26 July 1761, Johann Gottlob Lehmann found an orange-red mineral in the Ural Mountains which he named Siberian red lead. Events 657 - Battle of Siffin. 811 - Battle of Pliska; Byzantine Emperor Nicephorus Year 1761 ( MDCCLXI) was a Common year starting on Thursday (link will display the full calendar of the Gregorian calendar (or a Johann Gottlob Lehmann may refer to Johann Gottlob Lehmann (scientist ((1719–1767 German scientist and geologist Johann Gottlob Lehmann Riphean redirects here For the time period see Riphean stage The Ural Mountains (Ура́льские го́ры Uralskiye 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. Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Selenium (səˈliniəm is a Chemical element with the Atomic number 34 represented by the chemical symbol Se, an atomic mass of 78 Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Crocoite is a mineral consisting of Lead Chromate, PbCrO4 and crystallizing in the Monoclinic system

In 1770, Peter Simon Pallas visited the same site as Lehmann and found a red "lead" mineral that had very useful properties as a pigment in paints. Peter Simon Pallas ( September 22, 1741, Berlin — September 8, 1811, Berlin) was a German Zoologist For the drug referred to as "pigment" see Black tar heroin. Paint is any Liquid, liquifiable or mastic composition which after application to a substrate in a thin layer is converted to an opaque Solid The use of Siberian red lead as a paint pigment developed rapidly. A bright yellow made from crocoite also became fashionable. Yellow is the Color evoked by light that stimulates both the L and M (long and medium wavelength Cone cells of the Retina about equally

In 1797, Louis Nicolas Vauquelin received samples of crocoite ore. Louis Nicolas Vauquelin ( May 16, 1763 - November 14, 1829) was a French Pharmacist and Chemist. An ore is a volume of rock containing components or Minerals in a mode of occurrence that renders it valuable for mining He was able to produce chromium oxide with a chemical formula of CrO₃, by mixing crocoite with hydrochloric acid. Hydrochloric acid is the Solution of Hydrogen chloride ( H[[Chlorine Cl]] in water 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. A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive Mineral, which &mdash when cut and polished &mdash A Ruby is a pink to blood-red Gemstone, a variety of the Mineral Corundum ( Aluminium oxide) Emeralds are a variety of the Mineral Beryl (Be3Al2(SiO36 colored Green by trace amounts Later that year he successfully isolated elemental chromium.

During the 1800s chromium was primarily used as a component of paints and in tanning salts but now metal alloys account for 85% of the use of chromium. Tanning is the process of converting Putrescible skin into non-putrescible Leather, usually with Tannin, an Acidic Chemical compound The remainder is used in the chemical industry and refractory and foundry industries. The chemical industry comprises the companies that produce industrial chemicals A refractory is a material that retains its strength at high Temperatures ASTM C71 defines refractories as "non-metallic materials having those chemical and physical A foundry is a Factory which produces Metal Castings from either Ferrous or non-ferrous alloys

Chromium was named after the Greek word "Chrôma" meaning color, because of the many colorful compounds made from it.

Occurrence and production

World production trend

Chromium is mined as chromite (FeCr₂O₄) ore. Chromite is iron magnesium chromium oxide (Fe MgCr2O4 It is an Oxide Mineral belonging to the Spinel group About two-fifths of the chromite ores and concentrates in the world are produced in South Africa, while Kazakhstan, India, Russia, and Turkey are also substantial producers. The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa Kazakhstan, also Kazakstan ( Қазақстан, Qazaqstan, qɑzɑqˈstɑn Казахстан, Kazakhstán,) officially the India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending Turkey (Türkiye known officially as the Republic of Turkey ( is a Eurasian Country that stretches Untapped chromite deposits are plentiful, but geographically concentrated in Kazakhstan and southern Africa.

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. The United States dollar ( sign: $; code: USD) is the unit of Currency of the United States; it has also been

Though native chromium deposits are rare, some native chromium metal has been discovered. The Udachnaya Mine in Russia produces samples of the native metal. Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending This mine is a kimberlite pipe rich in diamonds, and the reducing environment so provided helped produce both elemental chromium and diamond. Kimberlite is a type of potassic Volcanic rock best known for sometimes containing Diamonds It is named after the town of Kimberley in South Africa (See also chromium minerals)

Chromium is obtained commercially by heating the ore in the presence of aluminium or silicon. An ore is a volume of rock containing components or Minerals in a mode of occurrence that renders it valuable for mining WikipediaNaming Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14

Chemical properties

Chromium

Chromium is a member of the transition metals, in group 6. In Chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings It commonly refers to any element in 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. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. +1, +4 and +5 are rare. Chromium compounds of oxidation state +6 are powerful oxidants.

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. Passivation is the process of making a material "passive" in relation to another material prior to using the materials together It forms a compound called a spinel structure which, being very dense, prevents diffusion of oxygen into the underlying layer. The spinels are any of a class of Minerals of general formulation XY2 O 4 which Crystallize in the cubic (isometric (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. Hydrogen embrittlement (or hydrogen grooving) is the process by which various metals most importantly high-strength Steel, become brittle and crack following exposure It does though suffer from nitrogen embrittlement and hence no straight chromium alloy has ever been developed. Below the pourbaix 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.

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

Compounds

Main article: Chromium compounds

Potassium dichromate is a powerful oxidizing agent and is the preferred compound for cleaning laboratory glassware of any trace organics. In Chemistry, a Pourbaix diagram, also known as a potential/pH diagram, maps out possible stable ( equilibrium) phases of an aqueous electrochemical system Potassium dichromate, K2Cr2O7 is a common inorganic chemical reagent most commonly used as an Oxidizing agent in various laboratory 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. Sodium dichromate is the Chemical compound with the formula Na2Cr2O7 20 g/100 ml respectively). Chrome green is the green oxide of chromium, Cr₂O₃, used in enamel painting, and glass staining. Chromium(III oxide is the Inorganic compound of the formula Cr2O3 An enamel paint is a Paint that dries to an extremely hard usually glossy finish Chrome yellow is a brilliant yellow pigment, PbCrO₄, used by painters. Chrome Yellow is a natural Yellow Pigment made of Lead(II chromate (PbCrO4

Chromic acid has the hypothetical structure H₂CrO₄. Chromic acid generally refers to a collection of compounds generated by the acidification of solutions containing Chromate and Dichromate anions or the 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, an anhydride is a compound that can be considered as derived from another compound by subtracting the molecules of water.

Chromium and the 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. In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon. In Chemistry, radicals (often referred to as free radicals) are atoms molecules or ions with Unpaired electrons on an otherwise Open shell X-ray scattering techniques are a family of non-destructive analytical techniques which reveal information about the crystallographic structure chemical composition A quintuple bond in Chemistry is an unusual type of Chemical bond first reported in 2005 for a di Chromium compound 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. A quintuple bond in Chemistry is an unusual type of Chemical bond first reported in 2005 for a di Chromium compound

Applications

Uses of chromium:

• In metallurgy, to impart corrosion resistance and a shiny finish:
  • as an alloy constituent, such as in stainless steel in cutlery
  • in chrome plating,
  • in anodized aluminium, literally turning the surface of aluminium into ruby. Metallurgy is a domain of Materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their An alloy is a Solid solution or Homogeneous mixture of two or more elements, at least one of which is a Metal, which itself has In Metallurgy, stainless steel is defined as a Steel Alloy with a minimum of 11 Cutlery refers to any hand Implement used in preparing serving and especially eating Food in the Western world. Chrome plating, often referred to simply as chrome, is a technique of Electroplating a thin layer of Chromium onto a Metal object Anodizing, or anodising, is an electrolytic Passivation process used to increase the thickness of the natural Oxide layer on the surface of metal WikipediaNaming A Ruby is a pink to blood-red Gemstone, a variety of the Mineral Corundum ( Aluminium oxide)
• As dyes and paints:
  • Chromium(III) oxide is a metal polish known as green rouge. Paint is any Liquid, liquifiable or mastic composition which after application to a substrate in a thin layer is converted to an opaque Solid Chromium(III oxide is the Inorganic compound of the formula Cr2O3
  • Chromium salts color glass an emerald green. Emeralds are a variety of the Mineral Beryl (Be3Al2(SiO36 colored Green by trace amounts
  • Chromium is what makes a ruby red, and therefore is used in producing synthetic rubies. A Ruby is a pink to blood-red Gemstone, a variety of the Mineral Corundum ( Aluminium oxide)
  • also makes a brilliant yellow for painting
• As a catalyst. Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst
• Chromite is used to make molds for the firing of bricks. Chromite is iron magnesium chromium oxide (Fe MgCr2O4 It is an Oxide Mineral belonging to the Spinel group A brick is a block of Ceramic material used in Masonry construction laid using mortar.
• Chromium salts are used in the tanning of leather. Tanning is the process of converting Putrescible skin into non-putrescible Leather, usually with Tannin, an Acidic Chemical compound Leather is a material created through the Tanning of hides and Skins of Animals primarily Cattlehide The Tanning process
• Potassium dichromate is a chemical reagent, used in cleaning laboratory glassware and as a titrating agent. A reagent or reactant is a substance or compound consumed during a Chemical reaction. Laboratory glassware refers to a variety of equipment traditionally made of Glass, used for Scientific experiments and other work in Science, especially It is also used as a mordant (i. A mordant is a substance used to set Dyes on fabrics by forming an insoluble compound with the dye 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. Chromium dioxide or chromium(IV oxide is a synthetic magnetic substance once widely used in Magnetic tape Emulsion. Magnetic tape is a medium for Magnetic recording generally consisting of a thin magnetizable coating on a long and narrow strip of Plastic. In Materials science, the coercivity, also called the coercive field, of a ferromagnetic material is the intensity of the applied Magnetic Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26
• In well drilling muds as an anti-corrosive.
• In medicine, as a dietary supplement or slimming aid, usually as chromium(III) chloride, chromium(III) picolinate, chromium(III) polynicotinate or as an amino acid chelate, such as chromium(III) D-phenylalanine. Chromium(III picolinate is the Chemical compound that is sold as a nutritional supplement to prevent or treat Chromium deficiency. ^[3]
• Chromium hexacarbonyl (Cr(CO)₆) is used as a gasoline additive. Chromium carbonyl, also known as chromium hexacarbonyl, is the Chemical compound with the formula Cr(CO6
• 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. For the drug referred to as "pigment" see Black tar heroin. Paint is any Liquid, liquifiable or mastic composition which after application to a substrate in a thin layer is converted to an opaque Solid 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 produce an Image, text, or Chrome plating, often referred to simply as chrome, is a technique of Electroplating a thin layer of Chromium onto a Metal object
• 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.

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. Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. Chromium deficiency is a disorder that results from an insufficient dietary intake of Chromium. In contrast, hexavalent chromium is very toxic and mutagenic when inhaled as publicized by the film Erin Brockovich. Hexavalent chromium ( 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) Erin Brockovich is a 2000 Drama film which dramatizes the story of Erin Brockovich 's first fight against the American West Coast 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). Contact dermatitis is a term for a Skin reaction resulting from exposure to Allergens (allergic contact dermatitis or irritants (irritant contact dermatitis ^[4]

Recently it was shown that the popular dietary supplement chromium picolinate complex generates chromosome damage in hamster cells. Chromium(III picolinate is the Chemical compound that is sold as a nutritional supplement to prevent or treat Chromium deficiency. 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). In the Metric system, a microgram is 1/1000000 of a Gram (1 × 10-6 or 1/1000 of a milligram is one of the smallest units of weight/mass commonly used ^[5]

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. Naturally occurring Chromium ( Cr) is composed of three stable Isotopes 52Cr 53Cr and 54Cr with 52Cr being Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides 789% natural abundance). In Chemistry, natural abundance (NA refers to the abundance Isotopes of a Chemical element as naturally found on a planet Nineteen radioisotopes have been characterized with the most stable being ⁵⁰Cr with a half-life of (more than) 1. 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 Half-Life (computer-game page here It's already listed in the disambiguation page 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. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. This element also has 2 meta states. A nuclear isomer is a Metastable state of an Atomic nucleus caused by the excitation of one or more of its Nucleons A nuclear isomer occupies

⁵³Cr is the radiogenic decay product of ⁵³Mn. A radiogenic Nuclide is one that is produced by a process of Radioactive decay. Manganese (ˈmæŋgəniːz is a Chemical element, designated by the symbol Mn. Chromium isotopic contents are typically combined with manganese isotopic contents and have found application in isotope geology. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides Manganese (ˈmæŋgəniːz is a Chemical element, designated by the symbol Mn. Isotope geochemistry is an aspect of Geology based upon study of the relative and absolute concentrations of the elements and their Isotopes in the Mn-Cr isotope ratios reinforce the evidence from ²⁶Al and ¹⁰⁷Pd for the early history of the solar system. Manganese (ˈmæŋgəniːz is a Chemical element, designated by the symbol Mn. WikipediaNaming Palladium (pronounced \pəˈleɪdiəm\ is a rare and lustrous silvery-white metal that was discovered in 1803 by William Hyde Wollaston, who named it palladium after the The Solar System consists of the Sun and those celestial objects bound to it by Gravity. 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. 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 atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass The unified atomic mass unit ( u) or Dalton ( Da) or sometimes universal mass unit, is an unit of Mass used to express The primary decay mode before the most abundant stable isotope, ⁵²Cr, is electron capture and the primary mode after is beta decay. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the In Nuclear physics, beta 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. ^[6] However, hexavalent chromium (chromium VI) compounds can be toxic if orally ingested or inhaled. Hexavalent chromium ( Cr(VI) compounds are those which contain the element Chromium in the +6 Oxidation state. Toxicity is the degree to which a substance is able to damage an exposed organism 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. The term carcinogen refers to any substance Radionuclide or radiation that is an agent directly involved in the promotion of Cancer or in the fatation of its propagation An investigation into hexavalent chromium release into drinking water formed the plot of the motion picture Erin Brockovich. Erin Brockovich is a 2000 Drama film which dramatizes the story of Erin Brockovich 's first fight against the American West Coast

World Health Organization recommended maximum allowable concentration in drinking water for chromium (VI) is 0. 05 milligrams per liter. For other uses of the words gram or gramme see Gram (disambiguation. The litre or liter (see spelling differences) is a unit of Volume. Hexavalent chromium is also one of the substances whose use is restricted by the European Restriction of Hazardous Substances Directive. The Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment 2002/95/EC ( / commonly referred to as the Restriction of Hazardous

Chromium salts (chromates) are also the cause of allergic reactions in some people. Chromates are often used to manufacture, amongst other things, leather products, paints, cement, mortar and anti-corrosives. Contact with products containing chromates leads to allergic contact dermatitis and irritant dermatitis, resulting in ulceration of the skin, sometimes referred to as "chrome ulcers". This condition is often found in workers that have been exposed to strong chromate solutions in electroplating, tanning and chrome-producing manufacturers. ^[7]

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 sites, now needing environmental cleanup and remediation per the treatment of brownfield land. A dye can generally be described as a Colored substance that has an affinity to the substrate to which it is being applied Paint is any Liquid, liquifiable or mastic composition which after application to a substrate in a thin layer is converted to an opaque Solid Tanning is the process of converting Putrescible skin into non-putrescible Leather, usually with Tannin, an Acidic Chemical compound Leather is a material created through the Tanning of hides and Skins of Animals primarily Cattlehide The Tanning process Groundwater is Water located beneath the Ground surface in Soil pore spaces and in the Fractures of lithologic formations Generally remediation means providing a Remedy, so environmental remediation deals with the removal of Pollution or Contaminants from environmental Primer paint containing hexavalent chromium is still widely used for aerospace and automobile refinishing applications. A primer is a preparatory coating put on materials before Painting Priming ensures better Adhesion of paint to the surface increases paint durability and provides This article is about the field of research and industry for the corporation see The Aerospace Corporation Aerospace comprises the

See also

• Chromium compounds
• Chromium minerals
• Chromium VI

References

• Los Alamos National Laboratory - Chromium
• WebElements.com – Chromium

External links

• IARC Monograph "Chromium and Chromium compounds"
• International Chromium Development Association
• It's Elemental – The Element Chromium
• National Pollutant Inventory - Chromium (III) compounds fact sheet
• The Merck Manual – Mineral Deficiency and Toxicity
• National Institute for Occupational Safety and Health - Chromium Page