Structural Problems and Non Stoichiometry in Thallium, Bismuth, and Lead Cuprates

Abstract

ABSTRACTAn over view of the crystal chemistry of the layered bismuth, thallium and lead cuprates is presented here. The classification of these oxides is examined, and the problems of non stoichiometry, especially of extented defects and incommensurability of the structures, are discussed in connection with the superconducting properties of these materials. A particular attention is paid for the role of the lone pair cations in the structural properties of these oxides.