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[en] The paper presents a generalized crystallochemical concept of mixed anion radicals - complex associations (different by their chemical and geometric nature) of amphoteric and (or) acid oxocomplexes in inorganic salts including minerals. Ti, B, Be, Nb, Zr, Mo, W, Sc, etc form a part of mixed anion radicals in addition to Al. Questions of nomenclature and classification of mixed anion radicals are considered and crystallochemical nature of their structural changeability related to morphotropy, polymorphism and polytypism is analyzed

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[en] Data on anisotropic specifications of the structural models of the Na₂Zn[SiO₄] (luminophore and piezoelectrjc, Rsub(hkl)=3.7%) and Na₂Be[SiO₄] (Rsub(hkl)=2.3%) compounds are presented. Similarity of the structural motives and their principal differences are pointed out for all the cations in tetrahedral aspect. Analysis of the ellipsoids of atom thermal vibrations is given. It is pointed out that anisotropy of atom thermal vibrations in the first compound is much higher than in the second one and it agrees with cleavage as to (012). Interatomic distances are determined

[en] General structural regularities are established and typical coordination numbers (c.n.) are found according to the data of the crystal-chemical analysis of oxygen-cadmium compound crystal structures(synthetical silicates, phosphates and germanates). It is shown that the c.n. change of Cd atoms depends mainly on the equilibrium of valent efforts on anions while forming respective structures. The c.n. change of cations is to a great extent due to the functioning of the first valency compensation mechanism at the formation of concrete crystal structures. It is shown that in the Cd₂G₂[GeO₄]O-compound c.n. increases up to 8, and in the Cd₅[PO₄]₃Cl one up to 9. The regularities observed permit to directly select conditions for crystal synthesis with the definite c.n. for some cations by changing the initial crystallization conditions from one class of compounds to another

[en] SrSiF₆x2H₂O compound is found to have a monoclinic symmetry. The parameters of the lattice cell are refined to be: a=10.760; b=5.892; c=9.462 A; γ=99.46 deg; Z=4; space group, P2₁/n; volume V=591.7 A³. Interatomic distances are presented. Electron density distribution is plotted

[en] High-temperature X-ray study of Na₅YSi₄O₁₂ monocrystal is carried out to clarify the character of temperature effect on structural parameters. Temperature dependence of Na₅YSi₄O₁₂ lattice parameters in the range of 22-500 deg is presented. Analysis of ellipsoids of thermal vibrations of alkali cations shows that cations Na₄, Na₅ and Na₆ make the main contribution to ionic conductivity. It the structure there is interconnection of two types of differently oriented conductivity channels - the rank of Na₅, Na₆ and the rank of Na₄ and Na₅. All the system of channels can be considered as three-dimensional

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