Structures of Tris -oxalato-complexes of Trivalent Metals

THE tris-oxalato-complexes of the general formula K3[M(C2O4)] xH2O (I), where M can be aluminium, vanadium, chromium, iron, cobalt, rhodium, iridium and several other metals [x varies, being 3 for aluminium, vanadium, chromium and iron; 3.5 for cobalt; and 4.5 for rhodium and iridium], have played a leading part in many aspects of co-ordination chemistry during the past 50 years. A great deal of work refers1 to their spectroscopic behaviour (where they are normally considered as tris-chelate compounds), their kinetic behaviour in solution, and, in some cases, their resolution into enantiomers.