A mercury pnictide halide semiconductor Hg19As10Br18（1） has been prepared by the solid-state reaction and structurally characterized by single-crystal X-ray diffraction analysis.Compound 1 crystallizes in triclinic,space group P with a = 11.262（4）,b = 11.352（4）,c = 12.309（5） ,α = 105.724（2）,β = 105.788（4）,γ = 109.0780（10）° and V = 1314.3（8） 3.The structure of 1 is composed of parallel perovskite-like layers bridged by the linearly coordinated Br atoms to form a three-dimensional framework.The optical properties were investigated in terms of the diffuse reflectance spectrum.The electronic band structure along with density of states（DOS） calculated by DFT method indicates that compound 1 is a semiconductor with an indirect band gap,and that the optical absorption is mainly originated from the charge transitions from Br-4p and As-4p to the Hg-6s states.
