A new semiconducting quaternary mixed halogenide: pentathallium dimercury pentabromide tetraiodide, Tl5Hg2Br5I4.

A novel quaternary mixed halogenide, Tl5Hg2Br5I4, was synthesized by fusion of thallium bromide and mercury iodide in a 5:2 molar ratio. The crystal structure of Tl5Hg2Br5I4 represents a new series of composite structures described by the general formula nTlBr*mTl2[HgBr2I2]; in this case, n = 4 and m = 8. Electronic structure calculations indicate that the title compound is a semiconductor.