The new quaternary sulfide La4MnCu6S10 has been synthesized by the reaction of La2S3, MnS, and CuS2 at 1223K. This compound crystallizes in a new structure type in space group P1̄ of the triclinic system with one formula unit in a cell of dimensions at 153K of a=6.6076(3)Å, b=7.3247(3)Å, c=8.7844(4)Å, α=83.457(1)°, β=74.398(1)°, γ=89.996(1)°, and V=406.61(3)Å3. The structure of La4MnCu6S10 consists of a three-dimensional framework of interconnected LaS7 monocapped trigonal prisms, MnS6 octahedra, and CuS4 tetrahedra. Band gaps of 2.49eV in the  direction and 2.53eV in the  direction have been derived from optical absorption measurements on a La4MnCu6S10 single crystal.
- Band gap in quaternary sulfide
- Lanthanum manganese copper sulfide
- Synthesis and X-ray structure