Труды сотрудников института физики

/ A. D. Vasiliev, N. M. Laptash // J. Struct. Chem. - 2012. - Vol. 53, Is. 5. - P. 902-906, DOI 10.1134/S0022476612050101. - Cited References: 11. - The work was supported by RFBR (grant No. 09-02-00062). . - ISSN 0022-4766РУБ Chemistry, Inorganic & Nuclear + Chemistry, Physical

Аннотация: X-ray crystallography is used to analyze the concomitant polymorphism of KNaNbOF5 crystals. The second beta-modification of the compound, crystallizing in the tetragonal crystal system is found for the first time: space group P4/nmm, a = 5.9352(2) , c =8.5487(5) , V = 301.14(2) (3), Z = 2, R1 = 0.0095. Parameters of the orthorhombic noncentrosymmetric structure of the alpha-phase, previously described by Poeppelmeier et al. (J. Am. Chem. Soc., 129, 13963-13969 (2007)), are refined and a comparative analysis of both structures is performed. The structures are characterized by the complete ordering of oxygen and fluorine atoms, the Nb-O distance in the alpha-phase (1.738(1) ) being noticeably longer than that in the beta-phase (1.709(2) ). In beta-KNaNbOF5, alternating NbOF5 and NaOF5 octahedra share vertices, while in alpha-KNaNbOF5, they share both vertices and edges. The existence of the non-polar centrosymmetric beta-modification of KNaNbOF5 cancels the assumption of the substantial contribution of potassium cations to the polar structure of alpha-KNaNbOF5.

Смотреть статью,
Scopus,
WoS,
Для получение полного текста обратитесь в библиотеку

Держатели документа:
[Vasiliev, A. D.] Russian Acad Sci, Siberian Div, LV Kirenskii Inst Phys, Krasnoyarsk, Russia
[Laptash, N. M.] Russian Acad Sci, Inst Chem, Far Eastern Div, Vladivostok 690022, Russia

Доп.точки доступа:
Laptash, N. M.; Васильев, Александр Дмитриевич