Indium tribromide, InBr₃

Indium tribromide, InBr₃, is prepared by the action of bromine vapour upon heated indium, and may be sublimed in a current of carbon dioxide. It resembles the trichloride in properties. Numerous physical properties of indium tribromide solutions have been measured by Heydweiller. The equivalent conductivities at 18° are as follows: -

v	9.9701	5.0000	2.0032	0.9962	0.5003	0.2640
1000η	0.1003	0.2000	0.4992	1.0038	1.9986	3.7875
λ	53.85	46.75	37.02	28.67	19.83	11.04

The double salts K₃InBr₆.2H₂O, (NH₄)₂InBr₅.H₂O, Rb₂InBr₅.H₂O, and Cs₂InBr₅.H₂O are isomorphous with the corresponding chlorine compounds.

The following densities (at 20°) and crystallographic constants are given by Wallace: -

Crystal symmetry	Compound	a:b:c	density
Tetragonal	K3InCl6.2H2O K3InBr6.2H2O	1:0.8173:0.8173:	2.483 3.140
Orthorombic	(NH4)2InCl5.H2O Rb2InCl5.H2O Cs2InCl5.H2O (NH4)2InBr5.H2O Rb2InBr5.H2O Cs2InBr5.H2O	0.9668:1:1.4005 0.9725:1:1.4085 0.9841:1:1.4033 0.9803:1:1.3951 0.9734:1:1.4180	2.281 3.089 3.350 3.167 3.409 3.776