Тип публикации: статья из журнала
Год издания: 2009
Идентификатор DOI: 10.1107/S0108270109010671
Ключевые слова: Average values, Experimental uncertainties, Fluoride ions, Mirror planes, Oxyfluoride, Structural units, Title compounds, Unit cells, Zigzag chains, Crystals, Ions, Stoichiometry, Aluminum, Tetra
Аннотация: Crystals of the title compound were extracted from the bulk of grown SrAlF(5) crystals as unexpected inclusions that were identified as the long sought after aluminium oxyfluoride. The structure of AlOF is built up from tetrahedral and octahedral polyhedra. Each tetrahedron is bisected by a mirror plane, with the Al atom and two veПоказать полностьюrtex anions in the plane. All tetrahedral vertices are positions of competing oxide and fluoride ions and are shared with octahedra. These shared vertices belong to two octahedral edges which join the octahedra 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 octahedral vertices are occupied only by fluoride ions. A small deficiency in the occupation of the octahedral 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) (tetrahedra), 1.800(2) (octahedra) and 1.894 (2) angstrom (octahedra). This structure differs widely from the reported tetragonal phase Al(1-x)O(1-3x)F(1+ 3x) (x = 0.0886) [Kutoglu (1992). Z. Kristallogr. 199, 197-201], which consists solely of octahedral structural units.
Журнал: ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS
Выпуск журнала: Vol. 65
Номера страниц: 20-22
ISSN журнала: 01082701
Место издания: MALDEN
Издатель: WILEY-BLACKWELL PUBLISHING, INC