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On the crystallochemical origin of the disordered form of Ba 7 (EuII) F 12 Cl 2 and the structural changes induced at high temperature
Author(s) -
Kubel F.,
Hagemann H.
Publication year - 2006
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.200610712
Subject(s) - electron microprobe , crystallography , chemistry , crystal structure , crystal (programming language) , structural change , mineralogy , computer science , economics , macroeconomics , programming language
The crystal structure of the disordered modification of Ba 7 F 12 Cl 2 has been carefully re‐examined on several new crystals prepared under different conditions of synthesis. All single crystal structure refinements reveal a residual electron density of ∼3 e – /Å 3 in the 0,0,0 position which is explained by the introduction of a small amount of sodium ions in the crystal. The title compound transforms from a disordered to an ordered modification at ∼800 °C. New structural data show a change in space group from P6 3 /m to P6. During this process, a slight chemical change and the formation of nano‐channels in the crystals is observed by electron microscopy. These changes were further studied by electron microprobe analysis, by spectroscopic methods and thermal analysis. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)