Gladyshevs'kyj R. Intermetallics and Oxides: from Ideal to Real Crystal Structure

In this work, the crystal chemistry of intermetallics and superconducting oxides, which is the basis for the development of new materials, was extended. Сrystal structures were studied by X-ray and neutron diffraction, phase analyses were performed by EDX, electron microscopy and DTA. Magnetic and electrical properties of superconducting cuprates were measured. The importance to distinguish between ideal, real and average crystal structures was emphasized. A classification of inorganic structure types, based on the space group and the Wyckoff sequence, was proposed. The crystal structures of 67 new intermetallics were determined (15 new structure types). It was shown that the reasons for the appearance of structural defects and the existence of closely related ideal structures are the same. A classification of high-Tc superconducting oxides was proposed. The crystal structures of 42 cuprates with new compositions were investigated (the phase (Bi/Pb)2Sr2Ca2Cu3O8F4 with fluorine was obtained for the firs t time, Tc=75 K). Methods for synthesis of superconducting ceramics (Tl/Pb)Sr2Ca2Cu3O9-d and improved technologies for the preparation of tapes with high critical current density were developed. Keywords: intermetallics, cuprates, superconductors, ideal structure, real structure, classification, synthesis, technology, superconducting tapes, critical current density