X-ray spectroscopic study of some ternary compounds of the type AIBIIIC2VIand AIBVC2VI

The chemical shifts Delta E of the copper K absorption discontinuity in compounds of the type A I B III C 2 VI (A=Cu; B=Al, Ga, In, Tl; C=S, Se, Te) and A I B V C 2 VI (A=Cu; B=Sb, Bi; C=S, Se, Te) with respect to the discontinuity in pure copper metal were measured using a Cauchois type bent crystal spectrograph of diameter 0.4 m. The observed chemical shifts have been correlated with the effective charge q on the copper ion in the materials. It is found that two separate Delta E versus q plots are obtained for the two different systems. It is shown that the intercept of the Delta E versus q plot gives an idea regarding the participation of the d-electrons of copper in the chemical bonding in these materials.