A New 1-D Chain of γ-Hg3S2Br2 Constructed from Hg4S4 Squares: Solid-state Synthesis, Structure and Optical Properties

A new metal chalcogenide, gamma-Hg3S2Br2 (1), has been prepared by moderate-temperature solidstate reaction, and its crystal structure was determined by single -crystal X-ray diffraction analysis. Compound 1 crystallizes in space group Cmmm of orthorhombic system with a = 9.1923(18), b = 18.2262(5), c = 4.6251(7) angstrom, V = 774.9(3) angstrom(3) and Z = 4. In the structure, two Hg(1), two Hg(2) and four S(1) atoms form a near square Hg4S4, and such squares are linked by Hg(3) atoms nearly linearly coordinated to two S1 atoms of two parallel Hg4S4 squares to form one-dimensional infinite Hg6S4 chains along c direction. Optical absorption spectra reveal the presence of sharp optical gap of 2.80 eV for 1. IR spectrum, TGA and electric resistivity have been investigated.