Molybdenum minerals have long been known, but the element was "discovered" (in the sense of differentiating it as a new entity from minerals salts of other metals) in 1778 by Carl Wilhelm Scheele who thought that he was observing lead while studying a sample of molybdenite. Named from the Greek word "molybdos, which actually means lead, Scheele notice an apparent visual similarity, which upon further analysis, proved to be incorrect. His studies led him to conclude that the ore sample did not contain lead, but a new element, which he named molybdenum after the mineral molybdenite.
Molybdenum is an element of the second transition series in Group 6 of the periodic table between chromium and tungsten.
As an alloy in steel it enhances strength, hardenability, weldability, toughness, elevated temperature strength, and corrosion resista
Molybdenum Properties
| Atomic number
| 42 |
| Atomic weight
| 95.96 |
| Crystal structure
| Body-centered cubic (BCC) |
| Lattice constant
| a = 3.1470 Å |
| Density:
| 10.22 g/cm3 |
| Melting temperature
| 2623 °C |
| Coefficient of thermal expansion
| 4.8 x 10-6 / K at 25 °C |
| Thermal conductivity
| 138 W/m K at 20°C |
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Unique properties, which make molybdenum metal and its alloys the material of choice in a variety of high tech applications, include high temperature strength, thermal and electrical conductivity, combined with low thermal expansion and environmental stability.
Chemically, the outstanding feature of molybdenum is its extraordinary versatility:
Oxidation states from –II to VI
Coordination numbers from 4 to 8
Varied stereochemistry
The ability to form compounds with inorganic and organic ligands, with particular preference for oxygen, sulfur, fluorine and chlorine donor atoms
Formation of bi- and poly-nuclear compounds containing bridging oxide or chloride ligands and/or molybdenum-molybdenum bonds.
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