Numéro
J. Phys. Colloques
Volume 47, Numéro C8, Décembre 1986
EXAFS and Near Edge Structure IV
Page(s) C8-803 - C8-807
DOI https://doi.org/10.1051/jphyscol:19868154
EXAFS and Near Edge Structure IV

J. Phys. Colloques 47 (1986) C8-803-C8-807

DOI: 10.1051/jphyscol:19868154

LOCAL STRUCTURE OF THE AgBr1-xIx ROCK-SALT TYPE SOLID-SOLUTION

A. YOSHIASA, K. KOTO, S. EMURA et F. KANAMARU

The Institute of Scientific and Industrial Research, Osaka University, Mihoga-oka, Ibaraki, Osaka 567, Japan


Abstract
The local structure of the AgBr1-xIx rock-salt type solid-solution (0≤x≤0.4) was discussed on the basis of both EXAFS and single crystal X-ray diffraction. The cell dimensions increase linearly with increasing AgI content because of substitution of larger ion I- for Br-. The average distance Ag-(Br,I) determined by X-ray diffraction increase apparently. However the interatomic distances between Ag and Br, which were determined by EXAFS on Ag K- and Br K-edge respectively, decrease with AgI content. The particular increase in temperature factor of Ag results from the displacements from the normal octahedral site owing to the fact that Br and I randomly occupy the normal site in the rock-salt type structure. Large shift of Ag K-edge was observed, indicating that the effective cation charge is lowered by replacing Br- with I-. Consequently, it should be expected that Ag in the solidsolution is attracted to Br- which has larger effective anion charge than I-.