Molybdenum
Molybdenum, Mo, is a transition metal element, found in
Group VIa of
the periodic table.
- Atomic Number : 42
- Relative Atomic Mass : 95.94
Discovery
Molybdenum was discovered by K W Scheele in 1778AD.
Molybdenum was isolated by P J Hjelm in 1790AD.
Occurrence
Molybdenum can be found as
- molybdenite, MoS2,
- wulfenite, PbMoO4, and
- molydite, MoO3.
Manufacture
Molybdenite is concentrated mechanically and then roasted to convert it
to the trioxide.
2 MoS2 + 7 O2 ==> 2 MoO3 + 4 SO2
Molybdenum metal is then made by firing the oxide with aluminium.
2 MoO3 + 4 Al ==> 2 Al2O3 + 2 Mo
Properties
Molybdenum is a hard white metal, which is stable in air at
room temperature.
Molybdenum is only slowly attacked by acids.
Reactions
Molybdenum is attacked slowly by dilute hydrochloric acid.
Uses
Molybdenum is an important component in steel alloys and in nickel
molybdenum steels used for the barrels of guns and propeller shafts.
Molybdenum is used as a support for filaments in electric lamps.
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