Some peculiarities of the formation of thallium-containing phases with perovskite-like structures

The authors systematize and analyse their own and described in literature experimental data on the composition and structure of high-temperature superconductors with thallium-containing phases. Some peculiarities of the isomorphic replacement and formation of thallium phases having single- and double-layered-type structure were found. Principles of crystallochemical formation of some phases, and chemical and thermal treatment allowing for their formation are described.