The chemical formula of "Molly" is MoS, and because of its layered structure it has a lubricating effect. Consisting of a sheet of molybdenum atoms squeezed between sheets of sulfur atoms, the atomic structure of molybdenite balances strong Mo-S bonds with weak sulfur bonds between layers. This results in effortless slippage and cleavage planes.
Occurring in high temperature hydrothermal ore deposits, molybdenite is associated with pyrite, quartz and fluorite (to name a few). The element rhenium readily substitutes for molybdenum which can result in a varying structure. Tracing the radioactive isotope rhenium-187 and the daughter isotope osmium-187 allows for geo-chronolgic dating, which is useful for determining dates of deposition and origin.
In World War I, the British replaced the manganese steel plating on their tanks with molybdenum steel plating, which allowed for higher speed, increased maneuverability and greater protection (despite being thinner). Current uses for molybdenum include being used as an adhesive between enamels and metals, as a fertilizer for some plants (including cauliflower) and in biological staining procedures.
Listed on the London Metal Exchange, molybdenum has a value of about $30,000/tonne (as of August 2009). Due to increased demand, it reached a peak of $103,000/tonne in June of 2005! It is the 54th most abundant element in the crust of the Earth and 42nd in the Universe. It was even discovered on the Moon by a Russian space mission.
Crystal System: Hexagonal
Cleavage: Perfect [0001]
Streak: bluish grey
Hardness:1-1.5
Luster: Metallic
Also Get to Know:
Molybdenite
Cummingtonite
Garnet
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