42 niobium ← molybdenum → technetium Cr ↑ Mo ↓ W Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	molybdenum, Mo, 42
Chemical series	transition metals
Group, Period, Block	6, 5, d
Appearance	gray metallic
Standard atomic weight	95.94(2)  g·mol−1
Electron configuration	[Kr] 4d5 5s1
Electrons per shell	2, 8, 18, 13, 1
Physical properties
Phase	solid
Density (near r.t.)	10. Niobium (naɪˈoʊbiəm or columbium (/kəˈlʌmbiəm/ is a Chemical element that has the symbol Nb and Atomic number 41 Technetium (tɛkˈniːʃɪəm is the lightest Chemical element with no Stable isotope. Chromium (ˈkroʊmiəm is a Chemical element which has the symbol Cr and Atomic number 24 Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 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 5 element is one of the Chemical elements in the fifth 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 In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other Krypton (ˈkrɪptən or /ˈkrɪptɒn/ from kryptos "hidden" is a Chemical element with the symbol Kr and Atomic number 36 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 28  g·cm−3
Liquid density at m.p.	9. 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. 33  g·cm−3
Melting point	2896 K (2623 °C, 4753 °F)
Boiling point	4912 K (4639 °C, 8382 °F)
Heat of fusion	37. 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 48  kJ·mol−1
Heat of vaporization	617  kJ·mol−1
Specific heat capacity	(25 °C) 24. 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 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 06  J·mol−1·K−1
Vapor pressure P(Pa) 1 10 100 1 k 10 k 100 k at T(K) 2742 2994 3312 3707 4212 4879
Atomic properties
Crystal structure	cubic body centered
Oxidation states	6, 5, 4, 3, 2, 1[1] (strongly acidic oxide)
Electronegativity	2. 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. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. 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 16 (Pauling scale)
Ionization energies (more)	1st:  684. 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 3  kJ·mol−1
	2nd:  1560  kJ·mol−1
	3rd:  2618  kJ·mol−1
Atomic radius	145  pm
Atomic radius (calc. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material 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 )	190  pm
Covalent radius	145  pm
Miscellaneous
Magnetic ordering	no data
Electrical resistivity	(20 °C) 53. 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. Electrical resistivity (also known as specific electrical resistance) is a measure of how strongly a material opposes the flow of Electric current. 4 n Ω·m
Thermal conductivity	(300 K) 138  W·m−1·K−1
Thermal expansion	(25 °C) 4. In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. When the Temperature of a substance changes the energy that is stored in the Intermolecular bonds between atoms changes 8  µm·m−1·K−1
Speed of sound (thin rod)	(r.t.) 5400  m·s−1
Young's modulus	329  GPa
Shear modulus	126  GPa
Bulk modulus	230  GPa
Poisson ratio	0. Sound is a vibration that travels through an elastic medium as a Wave. 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 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 31
Mohs hardness	5. 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	1530  MPa
Brinell hardness	1500  MPa
CAS registry number	7439-98-7
Selected isotopes
Main article: Isotopes of molybdenum iso NA half-life DM DE (MeV) DP 92Mo 14. 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 There are 35 known isotopes of Molybdenum ( Mo) ranging in Atomic mass from 83 to 117 as well as four metastable Nuclear isomers Seven isotopes 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 84% 92Mo is stable with 50 neutrons 93Mo syn 4×103 y ε - 93Nb 94Mo 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. 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 year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the Niobium (naɪˈoʊbiəm or columbium (/kəˈlʌmbiəm/ is a Chemical element that has the symbol Nb and Atomic number 41 25% 94Mo is stable with 52 neutrons 95Mo 15. 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. 92% 95Mo is stable with 53 neutrons 96Mo 16. 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. 68% 96Mo is stable with 54 neutrons 97Mo 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. 55% 97Mo is stable with 55 neutrons 98Mo 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. 13% 98Mo is stable with 56 neutrons 99Mo syn 65. 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. 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 94 h β- 0. The hour (symbol h) is a unit of Time. It is not an SI unit but is accepted for use with the SI In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted 436, 1. 214 99Tc γ 0. Technetium (tɛkˈniːʃɪəm is the lightest Chemical element with no Stable isotope. Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions 74, 0. 36, 0. 14 - 100Mo 9. 63% 7. 8×1018 y β-β- 3. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun In the process of Beta decay, unstable nuclei decay by converting a Neutron in the nucleus to a Proton and emitting an Electron and an electron 04 100Ru
References

Molybdenum (pronounced /məˈlɪbdənəm/, from the Greek meaning "lead-like"), is a Group 6 chemical element with the symbol Mo and atomic number 42. Ruthenium (ruːˈθiːniəm is a Chemical element that has the symbol Ru and Atomic number 44 Recommended values for many properties of the elements together with various references are collected on these data pages Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly 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 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 has the sixth-highest melting point of any element, and for this reason it is often used in high-strength steel alloys. Molybdenum is found in trace amounts in plants and animals, although excess molybdenum can be toxic in some animals. Molybdenum was discovered in 1778 by Carl Wilhelm Scheele and first isolated in 1781 by Peter Jacob Hjelm. Carl Wilhelm Scheele (9 December 1742 &ndash 21 May 1786 was a German - Swedish pharmaceutical chemist born in Stralsund, Western Pomerania, Peter Jacob Hjelm was a Swedisch chemist and the first person to isolate Molybdenum in 1781 four years after its discovery

Contents 1 Characteristics 2 Isotopes 3 Occurrence 4 Compounds 5 Biological role 5.1 Copper-molybdenum antagonism 6 Applications 7 History 8 Precautions 9 Supply and demand 10 References 11 External links

Characteristics

Molybdenum is a transition metal with an electronegativity of 1. In Chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings It commonly refers to any element in " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons 8 on the Pauling scale and an atomic mass of 95. 9 g/mole. ^[2] It does not react with oxygen or water at room temperature. At elevated temperatures, molybdenum trioxide is formed in the reaction 2Mo + 3O₂ → 2MoO₃. ^[3]

In its pure metal form, molybdenum is silvery white with a Mohs hardness of 5. 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, though it is somewhat more ductile than tungsten. Ductility is a mechanical property used to describe the extent to which materials can be deformed plastically or "stretched" into "wires" without It has a melting point of 2623°C, and only tantalum, osmium, rhenium, and tungsten have higher melting points. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. Tantalum (ˈtæntələm (formerly tantalium /tænˈtæliəm/ is a Chemical element with the symbol Ta and Atomic number 73 Osmium (ˈɒzmiəm is a Chemical element that has the symbol Os and Atomic number 76 Rhenium (ˈriːniəm is a Chemical element with the symbol Re and Atomic number 75 Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 ^[4] Molybdenum burns only at temperatures above 600°C. ^[5] It also has the lowest heating expansion of any commercially used metal. ^[6]

Molybdenum has a value of approximately $65,000 per tonne as of 4 May 2007. It maintained a price at or near $10,000 per tonne from 1997 through 2002, and reached a high of $103,000 per tonne in June 2005. ^[7]

Isotopes

Main article: Isotopes of molybdenum

There are 35 known isotopes of molybdenum ranging in atomic mass from 83 to 117, as well as four metastable nuclear isomers. There are 35 known isotopes of Molybdenum ( Mo) ranging in Atomic mass from 83 to 117 as well as four metastable Nuclear isomers Seven isotopes Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides 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 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 Seven isotopes occur naturally, with atomic masses of 92, 94, 95, 96, 97, 98, and 100. Of these naturally occurring isotopes, five are stable, with atomic masses from 94 to 98. All unstable isotopes of molybdenum decay into isotopes of niobium, technetium, and ruthenium. Niobium (naɪˈoʊbiəm or columbium (/kəˈlʌmbiəm/ is a Chemical element that has the symbol Nb and Atomic number 41 Technetium (tɛkˈniːʃɪəm is the lightest Chemical element with no Stable isotope. Ruthenium (ruːˈθiːniəm is a Chemical element that has the symbol Ru and Atomic number 44 ^[8]

Molybdenum-92 and molybdenum-100 are the only naturally occurring isotopes that are not stable. Molybdenum-100 has a half-life of approximately 1×10¹⁹ y and undergoes double beta decay into ruthenium-100. Half-Life (computer-game page here It's already listed in the disambiguation page A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun In the process of Beta decay, unstable nuclei decay by converting a Neutron in the nucleus to a Proton and emitting an Electron and an electron Ruthenium (ruːˈθiːniəm is a Chemical element that has the symbol Ru and Atomic number 44 Molybdenum-98 is the most common isotope, comprising 24. 14% of all molybdenum. Molybdenum isotopes with mass numbers from 111 to 117 all have half-lives of approximately . 15 μs. ^[8]

Occurrence

The world's largest producers of molybdenum materials are the United States, Canada, Chile, Russia, and China. ^[9][6]

Though molybdenum is found in such minerals as wulfenite (PbMoO₄) and powellite (CaMoO₄), the main commercial source of molybdenum is molybdenite (MoS₂). A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Wulfenite is a Lead Molybdate Mineral with the formula Pb Mo[[oxygen O]]4 Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the For Enoch Powell see here. For his political philosophy known as Powellism see here. Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Molybdenite is a mineral of Molybdenum disulfide, Mo[[sulfur S]]2 Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 Molybdenum is mined as a principal ore, and is also recovered as a byproduct of copper and tungsten mining. ^[4] Large mines in Colorado (Climax) and in British Columbia yield molybdenite, while many porphyry copper deposits such as the Chuquicamata mine in northern Chile produce molybdenum as a byproduct of copper mining. The State of Colorado ( or chiefly by nonresidents) is a state located in the Rocky Mountain region of the United States of America. Climax was an unincorporated Mining Village and a former US Post Office located in Lake County Colorado. British Columbia (ˌbrɪtɨʃ kəˈlʌmbiə ( BC) ( (la Colombie-Britannique C Molybdenite is a mineral of Molybdenum disulfide, Mo[[sulfur S]]2 Porphyry copper deposits are Copper Orebodies which are associated with porphyritic Intrusive rocks Chuquicamata, or "Chuqui" as it is more familiarly known is a big open pit Copper mine in the north of Chile, 215 km northeast Chile, officially the Republic of Chile ( Spanish:) is a country in South America occupying a long and narrow Coastal strip wedged between the The Knaben mine in southern Norway was opened in 1885, making it the first molybdenum mine. It remained open until 1973.

Molybdenum is the 42nd-most-abundant element in the universe, and the 25th-most-abundant element in Earth's oceans, with an average of 10. 8 mt/km³. ^[5] The Russian Luna 24 mission discovered a single molybdenum-bearing grain (1 × 0. 6 µm) in a pyroxene fragment taken from Mare Crisium on the Moon. The pyroxenes are a group of important rock-forming Silicate minerals found in many Igneous and metamorphic rocks. Mare Crisium (the "sea of crises" is a Lunar mare located in the Moon 's Crisium basin just northeast of Mare Tranquillitatis. ^[10]

A side product of molybdenum mining is rhenium. Rhenium (ˈriːniəm is a Chemical element with the symbol Re and Atomic number 75 As it is always present in small varying quantities in molybdenite, the only commercial source for rhenium is molybdenum mines.

Compounds

See also: Category:Molybdenum compounds

Molybdenum has several common oxidation states, +2 +3 +4 +5 and +6. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. The highest oxidation state is common in the molybdenum(VI) oxide MoO₃ while the normal sulfur compound is molybdenum disulfide MoS₂. Molybdenum(VI oxide is Chemical compound with the formula MoO sub>3 Molybdenum disulfide is the inorganic compound with the formula MoS2 The broad range of oxidation states shows up in the chlorides of molybdenum:

• Molybdenum(II) chloride MoCl₂ (yellow solid),
• Molybdenum(III) chloride MoCl₃ (dark red solid),
• Molybdenum(V) chloride MoCl₅ (dark green solid),
• Molybdenum(VI) chloride MoCl₆ (brown solid),

Like chromium and some other transition metals molybdenum is able to form quadruple bonds

Biological role

The most important use of the molybdenum atom in living organisms is as a metal hetero-atom at the active site in certain enzymes. Molybdenum dichloride describes Chemical compounds with the empirical formula MoCl2 Molybdenum pentachloride is the chemical compound with the formula MoCl5 Chromium (ˈkroʊmiəm is a Chemical element which has the symbol Cr and Atomic number 24 A quadruple bond is a type of Chemical bond between two Atoms involving 8 Electrons This bond is an extension of the more familiar types Double bonds In nitrogen fixation in certain bacteria, the nitrogenase enzyme which is involved in the terminal step of reducing molecular nitrogen, usually contains molybdenum in the active site (though replacement of Mo with iron or vanadium is known). Nitrogen fixation is the process by which Nitrogen is taken from its natural relatively inert molecular form (N2 in the atmosphere and converted into Nitrogenase ( is the Enzyme used by some organisms to fix atmospheric Nitrogen gas (N2

In March 2008, researchers reported that they had found strong evidence for the hypothesis that a scarcity of molybdenum in the earth's early oceans was a limiting factor in the further evolution of eukaryotic life (which includes all plants and animals) as eukaryotes cannot fix nitrogen and must acquire it from prokaryotic bacteria. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex [1] [2] The scarcity of molybdenum resulted from the relative lack of oxygen in the early ocean. Oxygen dissolved in seawater is the primary mechanism for dissolving molybdenum from minerals on the sea bottom.

Though molybdenum forms compounds with various organic molecules, including carbohydrates and amino acids, it is transported throughout the human body as MoO₄^2-. An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. Carbohydrates (from ' Hydrates of Carbon ' or saccharides ( Greek σάκχαρον meaning " Sugar " are the most In Chemistry, an amino acid is a Molecule containing both Amine and Carboxyl Functional groups In Biochemistry, this ^[11] Molybdenum is present in approximately 20 enzymes in animals, including aldehyde oxidase, sulfite oxidase, xanthine oxidase. Aldehyde oxidase is an Enzyme which generates Carboxylic acids from Aldehydes Sulfite oxidase ( is a biologically important enzyme found in all living organisms The Enzyme xanthine oxidase, or XO, (bovine milk enzyme is,) catalyzes the Oxidation of Hypoxanthine to Xanthine and can further ^[6] In some animals, the oxidation of xanthine to uric acid, a process of purine catabolism, is catalyzed by xanthine oxidase, a molybdenum-containing enzyme. Xanthine (ˈzænθiːn ˈzænθaɪn] (37-dihydro-purine-26-dione is a Purine base found in most body tissues and fluids and in other organisms Uric acid (or urate) is an Organic compound of Carbon, Nitrogen, Oxygen and Hydrogen with the formula C5H4N4O3 Purine ( 1) is a heterocyclic Aromatic Organic compound, consisting of a Pyrimidine ring fused to an Imidazole ring For the related metabolic process see Anabolism. Catabolism is the set of Metabolic pathways which break down molecules into The Enzyme xanthine oxidase, or XO, (bovine milk enzyme is,) catalyzes the Oxidation of Hypoxanthine to Xanthine and can further The activity of xanthine oxidase is directly proportional to the amount of molybdenum in the body. However, an extremely high concentration of molybdenum reverses the trend, and can act as an inhibitor in both purine catabolism and other processes. Molybdenum concentrations also affect protein synthesis, metabolism, and growth. Protein synthesis is the creation of proteins using DNA and' RNA'. Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. ^[11] These enzymes in plants and animals catalyse the reaction of oxygen in small molecules, as part of the regulation of nitrogen-, sulfur- and carbon cycles. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the The nitrogen cycle is the Biogeochemical cycle that describes the transformations of Nitrogen and nitrogen-containing compounds in nature Sulfur is one of the constituents of many Proteins Vitamins and Hormones It recycles as in other Biogeochemical cycles The essential The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the Biosphere, Pedosphere, Geosphere, Hydrosphere, and

In a 70 kg human body, there is approximately 9. 3 mg molybdenum, comprising . 00001% of the total body mass. ^[12] It occurs in higher concentrations in the liver and kidneys, and in lower concentrations in the vertebrae. ^[5] Molybdenum is also present within human tooth enamel and may help prevent the decaying thereof. Tooth enamel is the hardest and most highly mineralized substance of the body and with Dentin, Cementum, and dental pulp is one of the four major ^[13] Pork, lamb, and beef liver each have approximately 1. 5 parts molybdenum per million. Other significant dietary sources include green beans, eggs, sunflower seeds, wheat flour, lentils, and cereal grain. ^[6]

The average daily intake of molybdenum is . 3 mg. Acute toxicity hasn't been seen in humans, and the toxicity depends strongly on the chemical state. Rats show LD₅₀ as low as 180 mg/kg for some Mo compounds. ^[14] Molybdenum deficiency is not usually seen in healthy people. ^[15] Sodium tungstate is a competitive inhibitor of molybdenum. Sodium tungstate, Na2WO4 a Tungstate of Sodium, is useful as a source of Tungsten. Competitive inhibition is a form of enzyme inhibition where binding of the inhibitor to the Enzyme prevents binding of the substrate and vice versa Dietary tungsten reduces the concentration of molybdenum in tissues. Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 ^[5]

Copper-molybdenum antagonism

High amounts of molybdenum can interfere with the body's uptake of copper, both by preventing plasma proteins from binding the copper and by increasing the amount of copper that is excreted in urine. Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 Urine is a liquid waste product of the body secreted by the Kidneys by a process of filtration from Blood and Excreted through the Urethra. Ruminants that consume high amounts of molybdenum develop symptoms including diarrhea, stunted growth, anemia, and achromotrichia. Physiologically a ruminant is a Mammal of the order Artiodactyla that digests plant-based food by initially softening it within the animal's first stomach known In Medicine, diarrhea, also spelled diarrhoea (see spelling differences) is frequent loose or liquid Bowel movements Acute diarrhea Anemia ( AmE) or anæmia/anaemia ( BrE) (from the Ancient Greek grc-Latn anaîmia, meaning “without blood” is defined as a qualitative These symptoms can be alleviated by the administration of more copper into the system, both in dietary form and by injection. ^[16] The condition can be aggravated by excess sulfur. Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 ^[5]

Applications

The ability of molybdenum to withstand extreme temperatures without significantly expanding or softening makes it useful in applications that involve intense heat, including the manufacture of aircraft parts, electrical contacts, industrial motors, and filaments. ^[17][6] Molybdenum is also used in alloys for its high corrosion resistance and weldability. 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 Corrosion means the breaking down of essential properties in a material due to Chemical reactions with its surroundings The weldability of a material refers to its ability to be welded. ^[5][18] Most high-strength steel alloys are . 25% to 8% molybdenum. ^[4] Despite being used in such small portions, more than 43 million kg of molybdenum is used as an alloying agent each year in stainless steels, tool steels, cast irons, and high-temperature superalloys. In Metallurgy, stainless steel is defined as a Steel Alloy with a minimum of 11 Tool steel refers to a variety of Carbon and Alloy Steels that are particularly well-suited to be made into Tools Their suitability comes from Cast iron usually refers to grey cast iron, but identifies a large group of Ferrous Alloys which solidify with a Eutectic. A superalloy, or high-performance alloy, is an Alloy that exhibits excellent mechanical strength and creep resistance at high temperatures good surface ^[5]

Because of its lower density and more stable price, molybdenum is implemented in the place of tungsten. ^[5] Molybdenum can be implemented both as an alloying agent and as a flame-resistant coating for other metals. Although its melting point is 2623 °C, molybdenum rapidly oxidizes at temperatures above 760 °C, making it better-suited for use in vacuum environments. ^[17]

Molybdenum 99 is used as a parent radioisotope to the radioisotope Technetium 99, which is used in many medical procedures

Molybdenum disulfide (MoS₂) is used as a lubricant and an agent. Molybdenum disulfide is the inorganic compound with the formula MoS2 It forms strong films on metallic surfaces, and is highly resistant to both extreme temperatures and high pressure, and for this reason, it is a common additive to engine motor oil; in case of a catastrophic failure, the thin layer of molybdenum prevents metal-on-metal contact. Lead molybdate co-precipitated with lead chromate and lead sulfate is a bright-orange pigment used with ceramics and plastics. ^[19] Molybdenum trioxide (MoO₃) is used as an adhesive between enamels and metals. Molybdenum(VI oxide is Chemical compound with the formula MoO sub>3 ^[20] Molybdenum powder is used as a fertilizer for some plants, such as cauliflower. ^[5]

Also used in NO, NO2, NOx analyzers in power plants for pollution controls. At 350 °C the element acts as a catalyst for NO2/NOx to form only NO molecules for consistent readings by infrared light.

History

Molybdenite (from the Greek Μόλυβδος molybdos, meaning lead),^[4] the principal ore from which molybdenum is now extracted, was previously known as molybdena. Molybdena was confused with and often implemented as though it were graphite. The Mineral graphite, as with Diamond and Fullerene, is one of the Allotropes of carbon. Even when the two ores were distinguishable, molybdena was thought to be a lead ore. Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly ^[6] In 1754, Bengt Qvist examined the mineral and determined that it did not contain lead. ^[21]

It was not until 1778 that Swedish chemist Carl Wilhelm Scheele realized molybdena was neither graphite nor lead. "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation. Carl Wilhelm Scheele (9 December 1742 &ndash 21 May 1786 was a German - Swedish pharmaceutical chemist born in Stralsund, Western Pomerania, ^[20][22] He and other chemists then correctly assumed that it was the ore of a distinct new element, named molybdenum for the mineral in which it was discovered. Peter Jacob Hjelm successfully isolated molybdenum using carbon and linseed oil in 1781. Peter Jacob Hjelm was a Swedisch chemist and the first person to isolate Molybdenum in 1781 four years after its discovery Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Linseed oil, also known as flax seed oil or simply flax oil, is a clear to yellowish Drying oil derived from the dried ripe seeds of the Flax ^[6][23] For a long time there was no industrial use for molybdenum. The French Schneider Electrics company produced the first steel molybdenum alloy armor plates in 1894. Until World War I most other armor factories also used molybdenum alloys. World War I (abbreviated WWI; also known as the First World War, the Great War, and the War to End All In World War I, some British tanks were protected by 75 mm manganese plating, but this proved to be ineffective. World War I (abbreviated WWI; also known as the First World War, the Great War, and the War to End All Manganese (ˈmæŋgəniːz is a Chemical element, designated by the symbol Mn. The manganese plates were then replaced with 25 mm molybdenum plating. These allowed for higher speed, greater maneuverability, and, despite being thinner, better protection. ^[6] The high demand of molybdenum in World War I and World War II and the steep decrease after the wars had a great influence on prices and production of molybdenum. World War I (abbreviated WWI; also known as the First World War, the Great War, and the War to End All World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including

Precautions

Molybdenum dusts and fumes, as can be generated by mining or metalworking, are not toxic. There are no long-term effects associated with exposure to molybdenum; however, prolonged exposure can cause irritation to the eyes and skin. The direct inhalation or ingestion of molybdenum should also be avoided. ^[24] OSHA regulations specify the maximum permissible molybdenum exposure in an 8-hour day to be 5 mg/m³. The United States Occupational Safety and Health Administration (OSHA is an agency of the United States Department of Labor. Chronic exposure to 60 to 600 mg Mo/m³ can cause symptoms including fatigue, headaches, and joint pains. ^[25]

Supply and demand

Although current molybdenum production meets demand, refiners, or roasters, are expected to run into a shortfall between 2009 and 2015, depending on demand.

A roaster processes the moly into a fine powder, pellets, or other forms. Total world moly roaster capacity is currently 320 million pounds per year, barely enough to meet demand. There is not much excess roasting capacity, and no one is actively permitting for the production of any new roasters in the United States. Global roaster capacity also looks limited, and a future roaster shortage is predicted. The data above are based on the assumption that mines will be able to increase output.

Western demand is projected to increase by around 3 percent annually, while China and the CIS demand is projected to increase by around 10 percent annually, increasing overall global demand by around 4. 5 percent annually. Increasing demand can be attributed to two main factors. Hydroprocessing catalysts are becoming essential for crude oil. The other contributing factor is the increase in nuclear reactor construction. There are 48 nuclear reactors to be built by 2013, and approximately 100 are to be built by 2020. The International Molybdenum Association (IMOA) says that an average reactor contains about 520,000 feet of stainless steel alloy. Some larger reactors contain over 1 million feet of stainless steel alloy. Unless moly mine production picks up at a rapid pace, shortfalls of the metal are expected to arrive around 2009. ^[26]

References

External links

• WebElements.com — Molybdenum
• International Molybdenum Association — Main page

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