What is "molybdenite"

Molybdenite \Mo*lyb"de*nite\, n. [Cf. F. molybd['e]nite. See Molybdena.] (Min.) A mineral occurring in soft, lead-gray, foliated masses or scales, resembling graphite; sulphide of molybdenum.

n. (context mineralogy English) A mineral, molybdenum disulfide molybdenumsulfur₂, that is the principal ore of molybdenum; it is structurally similar to graphite and has a similar look and feel.

n. a mineral resembling graphite that is valued as the chief source of molybdenum and its compounds

Molybdenite is a mineral of molybdenum disulfide, Mo S. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum atoms sandwiched between sheets of sulfur atoms. The Mo-S bonds are strong, but the interaction between the sulfur atoms at the top and bottom of separate sandwich-like tri-layers is weak, resulting in easy slippage as well as cleavage planes. Molybdenite crystallizes in the hexagonal crystal system as the common polytype 2H and also in the trigonal system as the 3R polytype.