Gallium Halides - Monohalides

Monohalides

None of the monohalides are stable at room temperature. The previously reported GaBr and GaI produced from fusing gallium with the trihalide have been shown to be mixtures of metallic gallium with, respectively, Ga₂Br₃ and Ga₂I₃.

GaCl and GaBr

GaCl and GaBr have been produced in the gas form from the reaction of HX and molten gallium using a special reactor. They have been isolated by quenching the high temperature gas at 77 K. GaCl is reported as a red solid that disproportionates above 0 °C. Both GaCl and GaBr produced in this way can be stabilised in suitable solvents. The metastable solutions formed in this way have been used as precursors to numerous gallium cluster compounds.

In the HVPE production of GaN, GaCl is produced by passing HCl gas over molten gallium which is then reacted with NH₃ gas.

GaI

The chemical structure of the reagent termed ‘GaI’ produced from reacting gallium metal with iodine in toluene using ultrasound is not known. GaI is produced as a reactive green powder, which has been hailed as a “versatile reagent for the synthetic chemist”.