Crystal structures of dibromochloromethane and bromodichloromethane

Abstract

The crystal structures of CHB₂C1 and CHBrC1₂ have been investigated using neutron powder profile techniques. These structures were found to be similar to that of CHBr₃ in its lowest temperature triclinic phase. Whereas CHBr₃ has three phases, both CHBr₂C1 and CHBrC1₂ have only one. The two CHBr₃ phases which are absent in these compounds require the molecules to have threefold axes. The degree of disorder of the halogen atoms has been examined and the results indicate that the Br and C1 atoms have definite preferences for some sites over others, so that the molecules on average do not have a threefold axis.