Инд. авторы:	Vasiliev A.D., Melnikova S.V., Isaenko L.I.
Заглавие:	Ortho-rhom-bic aluminium oxyfluoride, AlOF
Библ. ссылка:	Vasiliev A.D., Melnikova S.V., Isaenko L.I. Ortho-rhom-bic aluminium oxyfluoride, AlOF // Acta Crystallographica Section C: Crystal Structure Communications. - 2009. - Vol.65. - Iss. 4. - P.i20-i22. - ISSN 0108-2701.
Внешние системы:	DOI: 10.1107/S0108270109010671; SCOPUS: 2-s2.0-64249107734;
Реферат:	eng: Crystals of the title compound were extracted from the bulk of grown SrAlF5 crystals as unexpected inclusions that were identified as the long sought after aluminium oxyfluoride. The structure of AlOF is built up from tetra-hedral and octa-hedral polyhedra. Each tetra-hedron is bisected by a mirror plane, with the Al atom and two vertex anions in the plane. All tetra-hedral vertices are positions of competing oxide and fluoride ions and are shared with octa-hedra. These shared vertices belong to two octa-hedral edges which join the octa-hedra to form infinite zigzag chains. The chains are strung along twofold screw axes that run parallel to the unit-cell b axis. The remaining two octa-hedral vertices are occupied only by fluoride ions. A small deficiency in the occupation of the octa-hedral Al position was suggested by the refinement. However, the stoichiometry of the compound is AlOF within experimental uncertainty. The Al - F(O) distances are separated into three groups with average values of 1.652 (3) (tetra-hedra), 1.800 (2) (octa-hedra) and 1.894 (2) Å (octa-hedra). This structure differs widely from the reported tetra-gonal phase Al1-x O1-3x F1+3x (x = 0.0886) [Kutoglu (1992). Z. Kristallogr. 199, 197-201], which consists solely of octa-hedral structural units. © 2009 International Union of Crystallography.
Ключевые слова:	Experimental uncertainties; Fluoride ions; Tetra; Aluminum; Stoichiometry; Ions; Average values; Zigzag chains; Unit cells; Title compounds; Structural units; Oxyfluoride; Mirror planes; Crystals;
Издано:	2009