KHo2CuSe4 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded in a 6-coordinate geometry to two equivalent Se(1) and four equivalent Se(2) atoms. Ho(1) is bonded to one Se(1), two equivalent Se(3), and three equivalent Se(2) atoms to form HoSe6 octahedra that share corners with three equivalent Ho(1)Se6 octahedra,  a cornercorner with one Cu(1)Se4 tetrahedra, edges with five equivalent Ho(1)Se6 octahedra, and edges with two equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 0-41°. Cu(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form CuSe4 tetrahedra that share corners with two equivalent Ho(1)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and edges with four equivalent Ho(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Ho(1), and two equivalent Cu(1) atoms. In the second Se site, Se(2) is bonded to two equivalent K(1), three equivalent Ho(1), and one Cu(1) atom to form a mixture of distorted corner, face, and edge-sharing SeK2Ho3Cu octahedra. The corner-sharing octahedral tilt angles are 62°. In the third Se site, Se(3) is bonded in a square co-planar geometry to four equivalent Ho(1) atoms.
KHo2CuSe4 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded in a 6-coordinate geometry to two equivalent Se(1) and four equivalent Se(2) atoms. Both K(1)-Se(1) bond lengths are 3.21 Å. All K(1)-Se(2) bond lengths are 3.33 Å. Ho(1) is bonded to one Se(1), two equivalent Se(3), and three equivalent Se(2) atoms to form HoSe6 octahedra that share corners with three equivalent Ho(1)Se6 octahedra,  a cornercorner with one Cu(1)Se4 tetrahedra, edges with five equivalent Ho(1)Se6 octahedra, and edges with two equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 0-41°. The Ho(1)-Se(1) bond length is 2.83 Å. Both Ho(1)-Se(3) bond lengths are 2.94 Å. There are two shorter (2.83 Å) and one longer (2.90 Å) Ho(1)-Se(2) bond length. Cu(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form CuSe4 tetrahedra that share corners with two equivalent Ho(1)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, and edges with four equivalent Ho(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 7°. Both Cu(1)-Se(1) bond lengths are 2.46 Å. Both Cu(1)-Se(2) bond lengths are 2.47 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Ho(1), and two equivalent Cu(1) atoms. In the second Se site, Se(2) is bonded to two equivalent K(1), three equivalent Ho(1), and one Cu(1) atom to form a mixture of distorted corner, face, and edge-sharing SeK2Ho3Cu octahedra. The corner-sharing octahedral tilt angles are 62°. In the third Se site, Se(3) is bonded in a square co-planar geometry to four equivalent Ho(1) atoms.