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Molybdenum,  42Mo
Molybdenum crystaline fragment and 1cm3 cube.jpg
General properties
Name, seembol molybdenum, Mo
Appearance gray metallic
Pronunciation ˌmɔɫɪbˈdinəm MOL-ib-DEE-nəm
or məˈɫɪbdɨnəm mə-LIB-di-nəm
Molybdenum in the periodic cairt
Hydrogen (diatomic nonmetal)
Helium (noble gas)
Lithium (alkali metal)
Beryllium (alkaline yird metal)
Boron (metalloid)
Carbon (polyatomic nonmetal)
Nitrogen (diatomic nonmetal)
Oxygen (diatomic nonmetal)
Fluorine (diatomic nonmetal)
Neon (noble gas)
Sodium (alkali metal)
Magnesium (alkaline yird metal)
Aluminium (post-transeetion metal)
Silicon (metalloid)
Phosphorus (polyatomic nonmetal)
Sulfur (polyatomic nonmetal)
Chlorine (diatomic nonmetal)
Argon (noble gas)
Potassium (alkali metal)
Calcium (alkaline yird metal)
Scandium (transeetion metal)
Titanium (transeetion metal)
Vanadium (transeetion metal)
Chromium (transeetion metal)
Manganese (transeetion metal)
Iron (transeetion metal)
Cobalt (transeetion metal)
Nickel (transeetion metal)
Copper (transeetion metal)
Zinc (transeetion metal)
Gallium (post-transeetion metal)
Germanium (metalloid)
Arsenic (metalloid)
Selenium (polyatomic nonmetal)
Bromine (diatomic nonmetal)
Krypton (noble gas)
Rubidium (alkali metal)
Strontium (alkaline yird metal)
Yttrium (transeetion metal)
Zirconium (transeetion metal)
Niobium (transeetion metal)
Molybdenum (transeetion metal)
Technetium (transeetion metal)
Ruthenium (transeetion metal)
Rhodium (transeetion metal)
Palladium (transeetion metal)
Siller (transeetion metal)
Cadmium (transeetion metal)
Indium (post-transeetion metal)
Tin (post-transeetion metal)
Antimony (metalloid)
Tellurium (metalloid)
Iodine (diatomic nonmetal)
Xenon (noble gas)
Caesium (alkali metal)
Barium (alkaline yird metal)
Lanthanum (lanthanide)
Cerium (lanthanide)
Praseodymium (lanthanide)
Neodymium (lanthanide)
Promethium (lanthanide)
Samarium (lanthanide)
Europium (lanthanide)
Gadolinium (lanthanide)
Terbium (lanthanide)
Dysprosium (lanthanide)
Holmium (lanthanide)
Erbium (lanthanide)
Thulium (lanthanide)
Ytterbium (lanthanide)
Lutetium (lanthanide)
Hafnium (transeetion metal)
Tantalum (transeetion metal)
Tungsten (transeetion metal)
Rhenium (transeetion metal)
Osmium (transeetion metal)
Iridium (transeetion metal)
Platinum (transeetion metal)
Gold (transeetion metal)
Mercur (transeetion metal)
Thallium (post-transeetion metal)
Lead (post-transeetion metal)
Bismuth (post-transeetion metal)
Polonium (post-transeetion metal)
Astatine (metalloid)
Radon (noble gas)
Francium (alkali metal)
Radium (alkaline yird metal)
Actinium (actinide)
Thorium (actinide)
Protactinium (actinide)
Uranium (actinide)
Neptunium (actinide)
Plutonium (actinide)
Americium (actinide)
Curium (actinide)
Berkelium (actinide)
Californium (actinide)
Einsteinium (actinide)
Fermium (actinide)
Mendelevium (actinide)
Nobelium (actinide)
Lawrencium (actinide)
Rutherfordium (transeetion metal)
Dubnium (transeetion metal)
Seaborgium (transeetion metal)
Bohrium (transeetion metal)
Hassium (transeetion metal)
Meitnerium (unkent chemical properties)
Darmstadtium (unkent chemical properties)
Roentgenium (unkent chemical properties)
Copernicium (transeetion metal)
Ununtrium (unkent chemical properties)
Flerovium (post-transeetion metal)
Ununpentium (unkent chemical properties)
Livermorium (unkent chemical properties)
Ununseptium (unkent chemical properties)
Ununoctium (unkent chemical properties)


Atomic nummer (Z) 42
Group, block group 6, d-block
Period period 5
Element category   transeetion metal
Staundart atomic wicht (±) (Ar) 95.95(1)
Electron configuration [Kr] 5s1 4d5
per shell
2, 8, 18, 13, 1
Pheesical properties
Phase solid
Meltin pynt 2896 K ​(2623 °C, ​4753 °F)
Boilin pynt 4912 K ​(4639 °C, ​8382 °F)
Density near r.t. 10.28 g/cm3
when liquid, at m.p. 9.33 g/cm3
Heat of fusion 37.48 kJ/mol
Heat o 598 kJ/mol
Molar heat capacity 24.06 J/(mol·K)
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2742 2994 3312 3707 4212 4879
Atomic properties
Oxidation states 6, 5, 4, 3, 2, 1[1], -1, -2
(strongly acidic oxide)
Electronegativity Pauling scale: 2.16
Atomic radius empirical: 139 pm
Covalent radius 154±5 pm
Crystal structur body-centered cubic (bcc)
Body-centered cubic crystal structur for molybdenum
Speed of sound thin rod 5400 m/s (at r.t.)
Thermal expansion 4.8 µm/(m·K) (at 25 °C)
Thermal conductivity 138 W/(m·K)
Thermal diffusivity 54.3[2] mm2/s (at 300 K)
Electrical resistivity 53.4 n Ω·m (at 20 °C)
Magnetic orderin paramagnetic[3]
Young's modulus 329 GPa
Shear modulus 126 GPa
Bulk modulus 230 GPa
Poisson ratio 0.31
Mohs haurdness 5.5
Vickers haurdness 1530 MPa
Brinell haurdness 1500 MPa
CAS Nummer 7439-98-7
Discovery Carl Wilhelm Scheele (1778)
First isolation Peter Jacob Hjelm (1781)
Maist stable isotopes o molybdenum
iso NA hauf-life DM DE (MeV) DP
92Mo 14.84% >1.9×1020 y (β+β+) 1.6491 92Zr
93Mo syn 4×103 y ε - 93Nb
94Mo 9.25% - (SF) <4.485
95Mo 15.92% - (SF) <4.531
96Mo 16.68% - (SF) <5.771
97Mo 9.55% - (SF) <6.226
98Mo 24.13% >1×1014 y ββ 0.1125 98Ru
99Mo syn 65.94 h β 0.436, 1.214 99mTc
γ 0.74, 0.36,
100Mo 9.63% 7.8×1018 y (ββ) 3.04 100Ru
Decay modes in parentheses is predict, but hisna yet been observed
· references

Molybdenum is a Group 6 chemical element wi the seembol Mo an atomic nummer 42. The name is frae Neo-Laitin Molybdaenum, frae Auncient Greek Μόλυβδος molybdos, meanin leid, syne its ores wur confused wi leid ores.[4] Molybdenum minerals hae been kent intae prehistory, but the element wis discovered (in the sense o differentiatin it as a new entity frae the mineral sauts o ither metals) in 1778 bi Carl Wilhelm Scheele. The metal wis first isolatit in 1781 bi Peter Jacob Hjelm.

Molybdenum disnae occur naiturally as a free metal on Yird, but rather in various oxidation states in minerals. The free element, whilk is a sillery metal wi a gray cast, haes the saxt-heichest meltin pynt o ony element. It readily furms haird, stable carbides in alloys, an for this raison maist o warld production o the element (aboot 80%) is in makin mony types o steel alloys, includin heich strength alloys an superalloys.

Maist molybdenum compounds hae law solubility in watter, but the molybdate ion MoO2−
is soluble an furms whan molybdenum-containin minerals are in contact wi oxygen an watter. Industrially, molybdenum compoonds (aboot 14% o warld production o the element) are uised in high-pressure an heich-temperatur applications, as pigments an catalysts.

Molybdenum-containin enzymes is bi far the maist common catalysts uised bi some bacteria tae break the chemical bond in atmospheric molecular nitrogen, allaein biological nitrogen fixation. At least 50 molybdenum-containin enzymes are nou kent in bacteria an ainimals, tho anly bacterial an cyanobacterial enzymes is involved in nitrogen fixation, an thirnitrogenases contain molybdenum in a different furm frae the rest. Awin tae the diverse functions o the various ither types o molybdenum enzymes, molybdenum is a required element for life in aw heicher organisms (eukaryotes), tho nae in aw bacteria.

References[eedit | eedit soorce]

  1. "Molybdenum: molybdenum(I) fluoride compound data". Retrieved 2007-12-10. 
  2. A. Lindemann, J. Blumm (2009). Measurement of the Thermophysical Properties of Pure Molybdenum. 17th Plansee Seminar. 
  3. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.
  4. Lide, David R., ed. (1994). "Molybdenum". CRC Handbook of Chemistry and Physics 4. Chemical Rubber Publishing Company. p. 18. ISBN 0-8493-0474-1.