Structure and bonding in chloro- and bromobismuthate(III) clusters (BiX4-, Bi2X93-, BiX63-) by NQR spectroscopy

Article abstract of DOI:10.1021/ic50205a032

The structural aspects of difficultly characterized halobismuthate(III) salts have been probed by using chlorine and bromine NQR spectroscopy. The presence of bridging and terminal halogen atoms is clearly evident in BiX₄^- and Bi₂X₉^3- salts, X = Cl, Br. Some BiX₆^3- salts contain discrete regular octahedral anions while others show evidence of bridging, or at least strongly associated, halogen atoms. The Raman spectra of these salts yield less decisive structural information than do the NQR spectra. General trends in ionicity as a function of the net charge on the structural unit are apparent in the NQR data now available for BiBr₂⁺, BiBr₃, BiBr₄^-, and BiBr₆^3- and BiCl₃, BiCl₄^-, and BiCl₆^3-. The bonding trend in M₂X₉^3-, M = Tl, Sb, Bi, is dominated by the effect of the ns² electron pair in the Sb and Bi.