Molybdenum(IV) bromide, also known as molybdenum tetrabromide, is the inorganic compound with the formula MoBr<sub>4</sub>. It is a black solid. MoBr<sub>4</sub> has been prepared by treatment of molybdenum(V) chloride with hydrogen bromide:
The reaction proceeds via the unstable molybdenum(V) bromide, which releases bromine at room temperature.
Molybdenum(IV) bromide can also be prepared by oxidation of molybdenum(III) bromide with bromine.