Indium(III) bromide

Indium(III) bromide, (indium tribromide), InBr₃, is a chemical compound of indium and bromine. It is a Lewis acid and has been used in organic synthesis.

It has the same crystal structure as aluminium trichloride, with 6 coordinate indium atoms. When molten it is dimeric, In₂Br₆, and predominantly dimeric in the gas phase. The dimer has bridging bromine atoms with a structure similar to dimeric aluminium trichloride Al₂Cl₆.

It is formed by the reaction of indium and bromine. InBr₃ forms complexes with ligands, L, InBr₃L, InBr₃L₂, InBr₃L₃.

Reaction with indium metal forms lower valent indium bromides, InBr₂, In₄Br₇, In₂Br₃, In₅Br₇, In₇Br₉, indium(I) bromide. In refluxing xylene solution InBr₃ and In metal react to form InBr₂.