Hydrothermal synthesis and crystal structure of lithium scandium orthophosphate Li2Sc[H(PO4)2]. The Li2MIII[H(PO4)2] family (MIII = Fe, Sc, In)

Autor: L. N. Komissarova, D. A. Rusakov, A. A. Filaretov, S. S. Khasanov, Sergey V. Simonov
Rok vydání: 2009
Předmět:
Zdroj: Russian Journal of Inorganic Chemistry. 54:1750-1762
ISSN: 1531-8613
0036-0236
Popis: Conditions 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) A, b = 8.198(2) A, c = 7.664(2) A, 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 \( \bar 1 \). 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.
Databáze: OpenAIRE
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