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Analysis of the Structural Phase Transition in Mixed Alkali Halide Crystals
Author(s) -
Shanker J.,
Sharma S. C.,
Kumar M.
Publication year - 1987
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221410206
Subject(s) - halide , alkali metal , chemistry , phase transition , lattice (music) , crystallography , crystal structure , thermodynamics , inorganic chemistry , physics , organic chemistry , acoustics
An analysis of structural transition in CsClKCl and CsClRbCl mixed crystals is presented by studying the lattice stability in terms of interionic potentials. The potential parameters are determined by fitting the experimental values of lattice energies in standard observed structure viz. CsCl structure for CsCl and CsBr crystals, and NaCl structure for RbCl and KCl crystals. It is found that CsClKCl mixed crystals remain stable in CsCl structure only for KCl less than 25%, and are transformed to NaCl structure when the proportion of KCl becomes equal to or more than 25%. For CsClRbCl mixed crystals, the transition from CsCl to NaCl structure is predicted when the RbCl component becomes equal to or more than 50%. These predictions are found to be in good agreement with experimental results. The lattice theory of structural stability is also applied to predict the transition temperatures for the mixed crystals viz. CsClKCl, CsClRbCl and CsClCsBr at which they transform from CsCl to NaCl structure.