Crystal structure of Molybdenum carbide

Molybdenum carbide (Mo2C) is a new type of material with high chemical stability, thermal stability, hardness and surface activity due to the intercalation structure formed by the insertion of carbon atoms, and its catalytic activity is similar to that of noble metals. Mo2C is widely used in the fields of electrocatalysts, ceramic materials, batteries and alloys.

Mo2C has a variety of crystal forms, but molybdenum carbide precipitated in steel has a hexagonal crystal structure of closely packed metal atoms, with the carbon atoms located halfway between the available octahedral interstices (but the carbon atom positions are assumed). The assumed lattice parameters in the figure below are a = 0.3007 nm and c = 0.4729 nm.

Projection of four unit cells. The numbers indicate the fractional coordinates along the z-axis. The black atoms are carbon and the blue molybdenum.