The melting reaction of copper, CuCl, sulfur, and Bi₂S ₃ yields black, shiny needles of the sulfide chloride Cu ₇Bi₆S₁₀Cl₅. The compound decomposes peritectically above 639(5) K. Cu-K-XANES data confirm the oxidation state +I of Cu. Cu₇Bi₆S_iCl₅ crystallizes in the monoclinic space group C2/m with a = 2878.3(9) pm, b = 396.59(9) pm, c = 1156.5(4) pm, and β = 111.55(3)° at T = 293(2) K. Three sulfur and four chlorine anions coordinate each of the threeindependent bismuth cations in the shape of mono-capped trigonal prisms. The [BiS₃Cl₄] polyhedra share edges and faces resulting in furrowed layers parallel (2̄01). Localized as well as disordered copper cations occupy trigonal or tetrahedral voids in the packing of anions. The Joint Probability Density Function (JPDF) reveals branched and unbranched continuous pathways along [010], which are available for cation conduction.