The three naturally occurring isomers of basic copper chloride, Cu₂(OH)₃C1, botallackite, paratacamite and atacamite, can be easily prepared from the reaction of cupric chloride with calcium carbonate, copper metal with cupric chloride and cuprous chloride with moisture, respectively. In contrast, variability in the nature of the isomer produced by other laboratory syntheses is observed. Botallackite, paratacamite and atacamite are readily distinguished by infra-red spectroscopy particulariy in the region 1000-300cm_-1, and this technique provides a quick and simple method for identifying the presence of one or a mixture of isomers on bronze antiquities. The infra-red spectra are illustrated.