Dy(CuSe)3 crystallizes in the trigonal R-3 space group. Dy(1) is bonded to six equivalent Se(1) atoms to form DySe6 octahedra that share corners with twelve equivalent Cu(1)Se4 tetrahedra, edges with three equivalent Dy(1)Se6 octahedra, and edges with six equivalent Cu(1)Se4 tetrahedra. Cu(1) is bonded to four equivalent Se(1) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent Dy(1)Se6 octahedra, corners with six equivalent Cu(1)Se4 tetrahedra, edges with two equivalent Dy(1)Se6 octahedra, and edges with three equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-60°. Se(1) is bonded in a 6-coordinate geometry to two equivalent Dy(1) and four equivalent Cu(1) atoms.
Dy(CuSe)3 crystallizes in the trigonal R-3 space group. Dy(1) is bonded to six equivalent Se(1) atoms to form DySe6 octahedra that share corners with twelve equivalent Cu(1)Se4 tetrahedra, edges with three equivalent Dy(1)Se6 octahedra, and edges with six equivalent Cu(1)Se4 tetrahedra. There are three shorter (2.87 Å) and three longer (2.88 Å) Dy(1)-Se(1) bond lengths. Cu(1) is bonded to four equivalent Se(1) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent Dy(1)Se6 octahedra, corners with six equivalent Cu(1)Se4 tetrahedra, edges with two equivalent Dy(1)Se6 octahedra, and edges with three equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-60°. There are a spread of Cu(1)-Se(1) bond distances ranging from 2.42-2.52 Å. Se(1) is bonded in a 6-coordinate geometry to two equivalent Dy(1) and four equivalent Cu(1) atoms.