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The Ternary System BaF 2 /CuF 2 /AlF 3 and the Crystal Structure of Ba 45 Cu 28 Al 17 F 197
Author(s) -
Dupont Nathalie,
Gredin Patrick,
Samouël Maurice,
Kozak Ariel de
Publication year - 2002
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/1521-3749(200201)628:1<191::aid-zaac191>3.0.co;2-c
Subject(s) - ternary operation , materials science , crystallography , crystal structure , chemistry , computer science , programming language
The ternary system BaF 2 /CuF 2 /AlF 3 is investigated by X‐ray diffraction techniques and an isothermal section at 620 °C is established. It exhibits ten quaternary phases and among them Ba 45 Cu 28 Al 17 F 197 . This fluoride has a triclinic cell: a = 14.024(1) Å, b = 23.778(1) Å, c = 25.480(1) Å, α = 90.44(1)°, β = 90.26(1)°, γ = 107.03(1)°, Z = 2. Its crystal structure was solved in the space group P1 (n o 1), from X‐ray single crystal data using 41976 unique reflections. It is built up from a complex arrangement of aluminium and copper fluorine polyhedra, which are regular [AlF 6 ] and strongly distorted [CuF 6 ] octahedra, [CuF 6 ] trigonal prisms and [Cu 2 F 10 ] bipolyhedral units constituted either by two octahedra, or one octahedron and one trigonal prism, connected by an edge. These polyhedra are organized in planes of about two octahedra thickness, which form a succession of sheets running perpendicularly to the [100] direction of the cell. Each sheet is constituted by infinite chains of distorted polyhedra connected by edges and vertices and linked together by the vertices of blocks of four and six polyhedra, involving aluminium fluorine octahedra and copper fluorine bipolyhedral units or octahedra. The barium ions, 10 to 14‐coordinated to fluorine atoms, ensure the electroneutrality of the structure. They are inserted inside the planes.