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New Heptafluorozirconates and ‐hafnates A I B II Zr(Hf)F 7 (A I = Rb, Tl; B II = Ca, Cd) – Synthesis, Structures, and Structural Relationships
Author(s) -
Meddar Lynda,
ElGhozzi Malika,
Avignant Daniel
Publication year - 2008
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/zaac.200700465
Subject(s) - orthorhombic crystal system , crystallography , pentagonal bipyramidal molecular geometry , crystal structure , stoichiometry , chemistry , powder diffraction , rietveld refinement , homologous series , single crystal , materials science
Four new ABZrF 7 heptafluorozirconates (A = Rb, Tl; B = Ca, Cd) and their homologous heptafluorohafnates, all colorless, orthorhombic Cmcm (n o 63), Z = 4, have been synthesized by heating stoichiometric mixtures of RbF or TlF, CaF 2 or CdF 2 and ZrF 4 (HfF 4 ) in sealed platinum tubes at temperature ranging from 550 °C (Tl) to 600 °C (Rb). The crystal structures of both RbCdZrF 7 and TlCdZrF 7 have been solved from single‐crystal X‐rays diffraction data. Rietveld refinements were performed from X‐rays powder patterns for RbCaZrF 7 and TlCaZrF 7 . In this series of heptafluorides, both B 2+ and Zr 4+ cations exhibit a pentagonal bipyramidal 7‐coordination. Their structural relationships with other heptafluorozirconates A I B II ZrF 7 as well as β‐KYb 2 F 7 are discussed. RbCaZrF 7 : a = 6.863(1) Å, b = 11.130(1) Å, c = 8.485(1) Å; TlCaZrF 7 : a = 6.868(1) Å, b = 11.165(1) Å, c = 8.486(1) Å; RbCdZrF 7 : a = 6.780(1) Å, b = 11.054(4) Å, c = 8.420(4) Å; TlCdZrF 7 : a = 6.784(3) Å, b = 11.099(2) Å, c = 8.424(9) Å.