Fe(CuS)2 crystallizes in the cubic F-43m space group. Fe(1) is bonded to one S(2) and three equivalent S(1) atoms to form FeS4 tetrahedra that share corners with four equivalent Cu(1)S4 tetrahedra, corners with six equivalent Fe(1)S4 tetrahedra, corners with six equivalent Cu(2)S4 tetrahedra, and edges with three equivalent Cu(1)S4 tetrahedra. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(2) and three equivalent S(1) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra, corners with six equivalent Cu(1)S4 tetrahedra, edges with three equivalent Fe(1)S4 tetrahedra, and edges with three equivalent Cu(2)S4 tetrahedra. In the second Cu site, Cu(2) is bonded to one S(3) and three equivalent S(1) atoms to form CuS4 tetrahedra that share corners with six equivalent Fe(1)S4 tetrahedra, corners with six equivalent Cu(2)S4 tetrahedra, and edges with three equivalent Cu(1)S4 tetrahedra. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to two equivalent Fe(1), two equivalent Cu(1), and two equivalent Cu(2) atoms. In the second S site, S(2) is bonded in a body-centered cubic geometry to four equivalent Fe(1) and four equivalent Cu(1) atoms. In the third S site, S(3) is bonded in a tetrahedral geometry to four equivalent Cu(2) atoms.
Fe(CuS)2 crystallizes in the cubic F-43m space group. Fe(1) is bonded to one S(2) and three equivalent S(1) atoms to form FeS4 tetrahedra that share corners with four equivalent Cu(1)S4 tetrahedra, corners with six equivalent Fe(1)S4 tetrahedra, corners with six equivalent Cu(2)S4 tetrahedra, and edges with three equivalent Cu(1)S4 tetrahedra. The Fe(1)-S(2) bond length is 2.35 Å. All Fe(1)-S(1) bond lengths are 2.29 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(2) and three equivalent S(1) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra, corners with six equivalent Cu(1)S4 tetrahedra, edges with three equivalent Fe(1)S4 tetrahedra, and edges with three equivalent Cu(2)S4 tetrahedra. The Cu(1)-S(2) bond length is 2.43 Å. All Cu(1)-S(1) bond lengths are 2.35 Å. In the second Cu site, Cu(2) is bonded to one S(3) and three equivalent S(1) atoms to form CuS4 tetrahedra that share corners with six equivalent Fe(1)S4 tetrahedra, corners with six equivalent Cu(2)S4 tetrahedra, and edges with three equivalent Cu(1)S4 tetrahedra. The Cu(2)-S(3) bond length is 2.24 Å. All Cu(2)-S(1) bond lengths are 2.41 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to two equivalent Fe(1), two equivalent Cu(1), and two equivalent Cu(2) atoms. In the second S site, S(2) is bonded in a body-centered cubic geometry to four equivalent Fe(1) and four equivalent Cu(1) atoms. In the third S site, S(3) is bonded in a tetrahedral geometry to four equivalent Cu(2) atoms.