Controlled reduction of MoO3 can produce different phases of catalytic
interest. One of these phases has been considered as being an oxycarb
ide of molybdenum. Various techniques mainly TEM but also XRD and othe
rs have been extensively used to understand the mechanism of formation
and the structure of this oxycarbide. Its structure is reminiscent of
the MoO3 structure as shown by XRD, but reconstructed by shear planes
and the introduction of carbon atoms to fill oxygen vacancies, both b
locking the formation of MoO2 the normal product of the slow reduction
of MoO3. The HRTEM pictures showed a 'chevron-like' arrangement and t
he electronic microdiffraction a square lattice reminiscent of the (Ok
O) planes of MoO3.