Study on Chemical Bond and Electronic State of New Gold Mixed Valence Complexes Cs_2Au~IX_2Au~(III)Y_4 (X, Y = Cl, Br, I) by Means of ~(197)Au Moessbauer Spectroscopy

摘要

Cs_2[Au~IX_2][Au~(III)X_4] (X = Cl, Br, I) is known for a perovskite-type gold mixed-valence system. We have synthesized new gold mixed valence complexes, Cs_2[Au~IX_2][Au~(III)Y_4] (X, Y = Cl, Br, I), which was proved by means of Raman spectroscopy. From the analysis of ~(197)Au Moessbauer spectra, it was elucidated that the charge transfer between Au~I(5d_(x~2-y~2)) and Au~(III)(5d_(x~2-y~2)) becomes to be predominant in the order of Y = Cl < Br < I for Cs_2[Au~IX_2][Au~(III)Y_4] (X, Y = Cl, Br,I).