There is evidence of dimerisation in the gaseous phase. The solid state structure is related to that of SnCl2 and PbCl2 and  the tin atoms have five near bromine atom neighbours in an approximately trigonal bipyramidal configuration.
There is proof of dimerization in the gaseous state. The solid-state structure is similar to that of SnCl2 and PbCl2, and the tin atoms have five near bromine atom neighbors in an approximately trigonal bipyramidal arrangement.