Isomorphism

Isomorphism (from Greek isos- equal and morphe- form), consists in the fact that different substances, similar in their chemical nature, crystallize in the same form and are capable of being precipitated from solutions in homogeneous crystals containing the most diverse quantitative relations of the bodies that entered into the crystals of similar substances. Isomorphism was discovered by Mitscherlich in 1819. The study of I. has been greatly advanced with the application of analysis of crystal structure by means of X-rays. Such an analysis showed that even mechanical mixing of certain substances (e.g. KCl and KBr) leads to the formation of isomorphous mixtures of these substances. The discovery of I. has rendered great service to chemistry and, in particular, to mineralogy, where many minerals diverse in composition were reduced to series of isomorphous mixtures.