Cu2SiS3 is Enargite-like structured and crystallizes in the monoclinic Cc space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(2), one S(3), and two equivalent S(1) atoms to form CuS4 tetrahedra that share corners with two equivalent Cu(1)S4 tetrahedra, corners with five equivalent Cu(2)S4 tetrahedra, and corners with five equivalent Si(1)S4 tetrahedra. In the second Cu site, Cu(2) is bonded to one S(1), one S(2), and two equivalent S(3) atoms to form CuS4 tetrahedra that share corners with two equivalent Cu(2)S4 tetrahedra, corners with five equivalent Cu(1)S4 tetrahedra, and corners with five equivalent Si(1)S4 tetrahedra. Si(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form SiS4 tetrahedra that share corners with two equivalent Si(1)S4 tetrahedra, corners with five equivalent Cu(1)S4 tetrahedra, and corners with five equivalent Cu(2)S4 tetrahedra. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Cu(2), two equivalent Cu(1), and one Si(1) atom to form SCu3Si tetrahedra that share corners with two equivalent S(1)Cu3Si tetrahedra, corners with five equivalent S(2)Cu2Si2 tetrahedra, and corners with five equivalent S(3)Cu3Si tetrahedra. In the second S site, S(2) is bonded to one Cu(1), one Cu(2), and two equivalent Si(1) atoms to form SCu2Si2 tetrahedra that share corners with two equivalent S(2)Cu2Si2 tetrahedra, corners with five equivalent S(1)Cu3Si tetrahedra, and corners with five equivalent S(3)Cu3Si tetrahedra. In the third S site, S(3) is bonded to one Cu(1), two equivalent Cu(2), and one Si(1) atom to form SCu3Si tetrahedra that share corners with two equivalent S(3)Cu3Si tetrahedra, corners with five equivalent S(2)Cu2Si2 tetrahedra, and corners with five equivalent S(1)Cu3Si tetrahedra.
Cu2SiS3 is Enargite-like structured and crystallizes in the monoclinic Cc space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(2), one S(3), and two equivalent S(1) atoms to form CuS4 tetrahedra that share corners with two equivalent Cu(1)S4 tetrahedra, corners with five equivalent Cu(2)S4 tetrahedra, and corners with five equivalent Si(1)S4 tetrahedra. The Cu(1)-S(2) bond length is 2.32 Å. The Cu(1)-S(3) bond length is 2.30 Å. There is one shorter (2.28 Å) and one longer (2.31 Å) Cu(1)-S(1) bond length. In the second Cu site, Cu(2) is bonded to one S(1), one S(2), and two equivalent S(3) atoms to form CuS4 tetrahedra that share corners with two equivalent Cu(2)S4 tetrahedra, corners with five equivalent Cu(1)S4 tetrahedra, and corners with five equivalent Si(1)S4 tetrahedra. The Cu(2)-S(1) bond length is 2.29 Å. The Cu(2)-S(2) bond length is 2.35 Å. There is one shorter (2.29 Å) and one longer (2.30 Å) Cu(2)-S(3) bond length. Si(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form SiS4 tetrahedra that share corners with two equivalent Si(1)S4 tetrahedra, corners with five equivalent Cu(1)S4 tetrahedra, and corners with five equivalent Cu(2)S4 tetrahedra. The Si(1)-S(1) bond length is 2.11 Å. The Si(1)-S(3) bond length is 2.11 Å. There is one shorter (2.24 Å) and one longer (2.26 Å) Si(1)-S(2) bond length. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Cu(2), two equivalent Cu(1), and one Si(1) atom to form SCu3Si tetrahedra that share corners with two equivalent S(1)Cu3Si tetrahedra, corners with five equivalent S(2)Cu2Si2 tetrahedra, and corners with five equivalent S(3)Cu3Si tetrahedra. In the second S site, S(2) is bonded to one Cu(1), one Cu(2), and two equivalent Si(1) atoms to form SCu2Si2 tetrahedra that share corners with two equivalent S(2)Cu2Si2 tetrahedra, corners with five equivalent S(1)Cu3Si tetrahedra, and corners with five equivalent S(3)Cu3Si tetrahedra. In the third S site, S(3) is bonded to one Cu(1), two equivalent Cu(2), and one Si(1) atom to form SCu3Si tetrahedra that share corners with two equivalent S(3)Cu3Si tetrahedra, corners with five equivalent S(2)Cu2Si2 tetrahedra, and corners with five equivalent S(1)Cu3Si tetrahedra.