BaCoCu3Se4 crystallizes in the monoclinic Cm space group. Ba(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form BaSe4 tetrahedra that share corners with four equivalent Co(1)Se4 tetrahedra, corners with four equivalent Cu(1)Se4 tetrahedra, and corners with eight equivalent Cu(2)Se4 tetrahedra. Co(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form CoSe4 tetrahedra that share corners with four equivalent Ba(1)Se4 tetrahedra, edges with two equivalent Cu(1)Se4 tetrahedra, and edges with four equivalent Cu(2)Se4 tetrahedra. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent Ba(1)Se4 tetrahedra, corners with eight equivalent Cu(2)Se4 tetrahedra, and edges with two equivalent Co(1)Se4 tetrahedra. In the second Cu site, Cu(2) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent Ba(1)Se4 tetrahedra, corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and edges with two equivalent Co(1)Se4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ba(1), one Co(1), one Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing SeBaCoCu3 trigonal bipyramids. In the second Se site, Se(2) is bonded to one Ba(1), one Co(1), one Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing SeBaCoCu3 trigonal bipyramids. In the third Se site, Se(3) is bonded to one Ba(1), one Co(1), one Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing SeBaCoCu3 trigonal bipyramids.
BaCoCu3Se4 crystallizes in the monoclinic Cm space group. Ba(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form BaSe4 tetrahedra that share corners with four equivalent Co(1)Se4 tetrahedra, corners with four equivalent Cu(1)Se4 tetrahedra, and corners with eight equivalent Cu(2)Se4 tetrahedra. The Ba(1)-Se(2) bond length is 3.00 Å. The Ba(1)-Se(3) bond length is 2.99 Å. Both Ba(1)-Se(1) bond lengths are 3.00 Å. Co(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form CoSe4 tetrahedra that share corners with four equivalent Ba(1)Se4 tetrahedra, edges with two equivalent Cu(1)Se4 tetrahedra, and edges with four equivalent Cu(2)Se4 tetrahedra. The Co(1)-Se(2) bond length is 2.31 Å. The Co(1)-Se(3) bond length is 2.31 Å. Both Co(1)-Se(1) bond lengths are 2.31 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent Ba(1)Se4 tetrahedra, corners with eight equivalent Cu(2)Se4 tetrahedra, and edges with two equivalent Co(1)Se4 tetrahedra. The Cu(1)-Se(2) bond length is 2.56 Å. The Cu(1)-Se(3) bond length is 2.56 Å. Both Cu(1)-Se(1) bond lengths are 2.56 Å. In the second Cu site, Cu(2) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent Ba(1)Se4 tetrahedra, corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and edges with two equivalent Co(1)Se4 tetrahedra. The Cu(2)-Se(2) bond length is 2.56 Å. The Cu(2)-Se(3) bond length is 2.56 Å. Both Cu(2)-Se(1) bond lengths are 2.56 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ba(1), one Co(1), one Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing SeBaCoCu3 trigonal bipyramids. In the second Se site, Se(2) is bonded to one Ba(1), one Co(1), one Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing SeBaCoCu3 trigonal bipyramids. In the third Se site, Se(3) is bonded to one Ba(1), one Co(1), one Cu(1), and two equivalent Cu(2) atoms to form a mixture of distorted corner and edge-sharing SeBaCoCu3 trigonal bipyramids.