A new metal chalcogenide,γ-Hg3S2Br2(1),has been prepared by moderate-temperature solid-state 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)?,V = 774.9(3)?3 and Z = 4.In the structure,two Hg(1),two Hg(2)and four S(l)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.