MoO2

MoO2 is an inorganic compound consisting of molybdenum and oxygen, with the formula MoO2. It appears as a black crystalline solid and is one of the lower oxides of molybdenum.

It crystallizes in a rutile-type tetragonal structure. The structure features chains of edge-sharing MoO6 octahedra aligned along the c-axis, producing anisotropic properties and quasi-one-dimensional conduction along the chains.

MoO2 is typically prepared by reducing MoO3 under hydrogen or forming gas at elevated temperatures. It can also be obtained by solid-state methods from MoO3 with reducing agents, or by deposition techniques such as chemical vapor deposition from Mo-containing precursors.

It exhibits metallic electrical conductivity, arising from partially filled Mo 4d bands, and has relatively high electronic mobility for an oxide. In air it is stable at room temperature but oxidizes to MoO3 upon heating or prolonged exposure at elevated temperatures.

It is used as a catalyst precursor and support in hydrocarbon processing and oxidation reactions. It also serves as a conductive material in thin-film coatings and electrodes for energy storage, and as a starting material for preparing MoS2 and other molybdenum oxides. In academia it is studied as a model system for rutile-type oxide conduction.

Related compounds include MoO3 and substoichiometric oxides such as MoO2+x; molybdenum metal is the elemental form related to its oxide chemistry.