The structures of the tetracyanoplatinates, a class of quasi-onedimensional systems

Abstract

Abstract A summary is given on the structures of the tetracyanoplatinates (with formal Pt oxidation number 2.0 – 2.49) with alkali, earth alkali and lanthanoid cations. The features common to the structures of the partially oxidized tetracyanoplatinates and the tetracyanoplatinates(II) are outlined. The role of the cations, anions and water molecules in determining the crystal structure is discussed. Special interest is laid on the great variation of the inchain Pt – Pt distance R from about 3.75 Å to 3.09 Å (for compounds with the formal Pt oxidation number of two) and further from 2.92 Å to 2.80 Å (for the partially oxidized compounds). Conditions for structures with small values of R are given. Small Pt – Pt distances R should hence be looked for in tetracyanoplatinates with cations of high polarizability, low water content and strongly polarizing anions.