Periodic errors in the crystal lattices of some molecular complexes of 4:4'-dinitrodiphenyl

Faults in the crystal lattices of the molecular complexes of 4:4'-dinitrodiphenyl with 4-chloro-diphenyl and 4:4'-diiododiphenyl have been observed. They appear to be of a similar nature to those discussed in a previous paper (James & Saunder, 1947). The complexes of 4:4'-dinitrodiphenyl with 4-fluorodiphenyl and 4:4'-dibromodiphenyl have also been examined, but their crystal lattices show no faults. It is suggested that the interaction of dipoles, and not chemical bonding, is responsible for the stability of complexes of this type.