ISSN:
0044-2313
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Jahn-Teller Effect and Crystal Structure Distortion of the Copper Fluoroperovskites NaCuF3 and RbCuF3The crystal structures of triclinic NaCuF3 (a = 539.1, b = 555.2, c = 792.8 pm, α = 90.66, β = 92.05, γ = 86.95°; P1, Z = 4) and of tetragonal RbCuF3, isotypic with KCuF3, (a = 602.3, c = 791.2 pm; I4/mcm, Z = 4), were determined by x-ray methods and refined to wR = 0.038 (2113 reflections) resp. 0.039 (257 reflections). The structures derive from orthorhombic (GdFeO)3 and cubic perovskite type, resp., by Jahn-Teller distortion. The CuF64- octahedra, differently elongated in the two compounds (average NaCuF3: Cu—F = 188.9/197.3/225.6(2) pm; RbCuF3: 188.3/197.8/237.6(3) pm), show the same pattern of antiferrodistortive ordering, but there are bent bridges Cu—F—Cu = 144.2…148.0(1)° in NaCuF3. Structural relations to the prototypes mentioned and to comparably Jahn-Teller distorted copper fluoro compounds are discussed.
Notes:
Die Kristallstrukturen des triklinen NaCuF3 (a = 539,1, b = 555,2, c = 792,8 pm, α = 90,66, β = 92,05, γ = 86,95°; P1, Z = 4) und des tetragonalen, mit KCuF3 isotypen RbCuF3 (a = 602,3, c = 791,2 pm; I4/mcm, Z = 4) wurden röntgenographisch bestimmt und auf wR = 0,038 (2113 Reflexe) bzw. 0,039 (257 Reflexe) verfeinert. Die Strukturen leiten sich vom orthorhombischen (GdFeO3-) bzw. kubischen Perowskit-Typ durch Jahn-Teller-Verzerrung ab. Die in beiden Verbindungen unterschiedlich gestreckten CuF64--Oktaeder (Mittelwert NaCuF3: Cu—F = 188,9/197,3/225,6(2) pm; RbCuF3: 188,3/197,8/237,6(3) pm) sind nach demselben Muster antiferrodistortiv geordnet, jedoch unter Winkelung Cu—F—Cu = 144,2…148,0(1)° in NaCuF3. Strukturelle Beziehungen zu den genannten Prototypen und zu vergleichbar Jahn-Teller-verzerrten Kupfer-Fluorverbindungen werden diskutiert.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/zaac.19905850112
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