A. A. Filaretov

Investigation of the structural conditionality for changes in physical properties of K3H(SO4)2 crystals

AbstractWith the aim of elucidating the nature of anomalies in the physical properties of K3H(SO4)2 crystals that arise as the temperature grows, the dielectric and optical properties of the crystals are studied, an X-ray diffraction analysis of single-crystal and polycrystalline specimens are performed, and the morphology and chemical composition are studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. As a result of the studies performed, a phase transition from the phase with the monoclinic symmetry (space group C2/c) to the phase with the trigonal symmetry (space group R

Indium strontium hydrogen phosphate SrIn2[PO3(OH)]4: Synthesis and crystal structure

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Phase formation in the Ag3PO4-ScPO4 quasi-binary system

m) is found in a number of K3H(SO4)2 specimens at a temperature of ≈457 K, the responsibility of the dynamically disordered hydrogen-bond system for the rise of high proton conductivity in the high-temperature phases of the crystals of this family is confirmed, and data on the solid-phase reactions proceeding at high temperatures are obtained.

Phase formation in the Ag3VO4-ScVO4 quasi-binary system

AbstractConditions of the hydrothermal synthesis of scandium hydrogen orthophosphate Li2Sc[H(PO4)2] (I) have been studied and the range of its monomineral crystallization have been determined. The existence of bound hydrogen in the structure has been confirmed by IR spectroscopy. The crystals of I are monoclinic: a = 4.857(1) Å, b = 8.198(2) Å, c = 7.664(2) Å, β = 104.097(5)°, space group P21/n, Z = 2. The structure was solved by direct methods and refined by full-matrix least-squares calculation in the anisotropic approximation for all non-hydrogen atoms, Robs = 0.0215, Rwall = 0.0335 (705 reflections with I > 3σ(I)). The basis of the structure is a mixed anionic para-framework {Sc[H(PO4)2]}3∞2−, composed of vertex-sharing ScO6 octahedra and PO4 tetrahedra. The structural unit of the para-framework is the microblock [ScP6O24] with symmetry

Complex phosphates containing mono- and trivalent cations

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Hydrothermal synthesis, structures, and properties: Indium hydrogen phosphates MIIn(HPO4)2 (Mi = K, Rb, and NH4)

. The microblocks are condensed in columns running in the [100] direction to form through channels filled with Li+ cations (CN = 5). A model with splitting of the hydrogen atom position implying the formation of a strong asymmetric nonlinear H-bond has been suggested and considered. The compound is stable to 400°C. The results of studying compound I are presented together with the data on the Fe- and In-containing Li2MIII[H(PO4)2] analogues.