Open AccessAn X‐ray diffraction analysis of potassium bromide
Author(s) -
Meisalo V.,
Inkinen O.
Publication year - 1967
Publication title -
acta crystallographica
Language(s) - English
Resource type - Journals
ISSN - 0365-110X
DOI - 10.1107/s0365110x67000118
Subject(s) - potassium , potassium bromide , bromide , diffraction , x ray crystallography , x ray , materials science , crystallography , chemistry , optics , physics , inorganic chemistry , metallurgy
The structure factors of potassium bromide were determined at 300 °K from the integrated intensities of Bragg reflexions from powder samples. The intensities were placed on an absolute scale by the direct intensity measurement of the primary X-ray beam. Extinction, surface roughness, and preferred orientation effects were found to be negligible. The values B~: = 2.45 + 0.15/~2 and BBr= 2"23 + 0"15/~,a were obtained for the temperature parameters, which correspond to the characteristic temperature Ou= 157 + 8°K. The crystal radii of the ions were evaluated as Ric= 1.57 + 0.07/~, and RBr= 1"73 + 0'07 A. The average electron density in the space outside the ionic spheres was found to be considerably low, as expected from the heteropolar character of the bonding in KBr. Deviations from spherical symmetry were revealed in the outer electron distributions of potassium and bromide ions. Both ions were shown to be compressed in the crystalline environment compared with the theoretical free ions. For the potassium ion the Hartree-Fock form factors showed a better agreement with the experimental values than those calculated from Dirac-Slater wave functions, while for the bromide ion the latter values were preferable.