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. 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) .The3. 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 primarily originated from the charge transitions from Br-4p and As-4p to the Hg-6s states.