Sixteen isomers of heterometallic germanium clusters have been analysed in this review. There are two types of
isomerism, distortion (x 15) and cis – trans (x 1) and cis – isomer contains two crystallographically independent molecules.
Distortion isomers, differing only by degree of distortion in Ge – L, Ge – M (M = metal) distances and L – Ge - L
(L = ligand) angles. The data are discussed with these found in the isomerism of germanium coordination compounds as
well as organogermanium derivatives. In the chemistry of germanium were found-seventy four derivatives as isomers.
These are discussed and compared with those in tin (over two hundred and fifty examples) and lead (seventy examples)
chemistry. This review and its precursors give the first overall survey of the structural data for the isomer complexes of
the group IV metals.