Preparation of vanadium(V) oxide tribromide, vanadium(IV) oxide dibromide, and their reactions with ammonia

Abstract

Vanadium(V) oxide tribromide can be prepared in good yield by the reaction between vanadium(V) oxide trichloride and hydrogen bromide at 0°. Vanadium(IV) oxide dibromide is obtained by thermal decomposition of vanadium(V) oxide tribromide. Both these halides are soluble in liquid ammonia; VOBr₂ gives the penta-ammoniate [VO(NH₃)₅]Br₂, while VOBr₃ undergoes ammonolysis and reduction.