Yb(HoSe2)2 crystallizes in the orthorhombic Pnma space group. Yb(1) is bonded to two equivalent Se(1), two equivalent Se(2), and three equivalent Se(3) atoms to form distorted YbSe7 pentagonal bipyramids that share corners with four equivalent Ho(1)Se6 octahedra, corners with four equivalent Ho(2)Se6 octahedra,  an edgeedge with one Ho(1)Se6 octahedra, edges with four equivalent Ho(2)Se6 octahedra, edges with two equivalent Yb(1)Se7 pentagonal bipyramids, and faces with two equivalent Yb(1)Se7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 12-67°. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(4) atoms to form HoSe6 octahedra that share corners with three equivalent Ho(2)Se6 octahedra, corners with four equivalent Yb(1)Se7 pentagonal bipyramids, edges with two equivalent Ho(2)Se6 octahedra, edges with four equivalent Ho(1)Se6 octahedra, and  an edgeedge with one Yb(1)Se7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 51-59°. In the second Ho site, Ho(2) is bonded to one Se(2), one Se(4), two equivalent Se(1), and two equivalent Se(3) atoms to form HoSe6 octahedra that share corners with three equivalent Ho(1)Se6 octahedra, corners with four equivalent Yb(1)Se7 pentagonal bipyramids, edges with two equivalent Ho(1)Se6 octahedra, edges with two equivalent Ho(2)Se6 octahedra, and edges with four equivalent Yb(1)Se7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 51-59°. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Yb(1), one Ho(1), and two equivalent Ho(2) atoms to form distorted SeYb2Ho3 trigonal bipyramids that share corners with two equivalent Se(2)Yb2Ho3 square pyramids, corners with six equivalent Se(3)Yb3Ho2 square pyramids, edges with two equivalent Se(3)Yb3Ho2 square pyramids, edges with three equivalent Se(2)Yb2Ho3 square pyramids, and edges with two equivalent Se(1)Yb2Ho3 trigonal bipyramids. In the second Se site, Se(2) is bonded to two equivalent Yb(1), one Ho(2), and two equivalent Ho(1) atoms to form SeYb2Ho3 square pyramids that share corners with two equivalent Se(3)Yb3Ho2 square pyramids, corners with two equivalent Se(1)Yb2Ho3 trigonal bipyramids, edges with two equivalent Se(2)Yb2Ho3 square pyramids, edges with three equivalent Se(3)Yb3Ho2 square pyramids, and edges with three equivalent Se(1)Yb2Ho3 trigonal bipyramids. In the third Se site, Se(3) is bonded to three equivalent Yb(1) and two equivalent Ho(2) atoms to form SeYb3Ho2 square pyramids that share corners with two equivalent Se(2)Yb2Ho3 square pyramids, corners with six equivalent Se(1)Yb2Ho3 trigonal bipyramids, edges with three equivalent Se(2)Yb2Ho3 square pyramids, edges with four equivalent Se(3)Yb3Ho2 square pyramids, and edges with two equivalent Se(1)Yb2Ho3 trigonal bipyramids. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Ho(2) and three equivalent Ho(1) atoms.
Yb(HoSe2)2 crystallizes in the orthorhombic Pnma space group. Yb(1) is bonded to two equivalent Se(1), two equivalent Se(2), and three equivalent Se(3) atoms to form distorted YbSe7 pentagonal bipyramids that share corners with four equivalent Ho(1)Se6 octahedra, corners with four equivalent Ho(2)Se6 octahedra,  an edgeedge with one Ho(1)Se6 octahedra, edges with four equivalent Ho(2)Se6 octahedra, edges with two equivalent Yb(1)Se7 pentagonal bipyramids, and faces with two equivalent Yb(1)Se7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 12-67°. Both Yb(1)-Se(1) bond lengths are 3.11 Å. Both Yb(1)-Se(2) bond lengths are 2.98 Å. There are two shorter (2.95 Å) and one longer (3.02 Å) Yb(1)-Se(3) bond length. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(4) atoms to form HoSe6 octahedra that share corners with three equivalent Ho(2)Se6 octahedra, corners with four equivalent Yb(1)Se7 pentagonal bipyramids, edges with two equivalent Ho(2)Se6 octahedra, edges with four equivalent Ho(1)Se6 octahedra, and  an edgeedge with one Yb(1)Se7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 51-59°. The Ho(1)-Se(1) bond length is 2.87 Å. Both Ho(1)-Se(2) bond lengths are 2.83 Å. There are two shorter (2.82 Å) and one longer (2.91 Å) Ho(1)-Se(4) bond length. In the second Ho site, Ho(2) is bonded to one Se(2), one Se(4), two equivalent Se(1), and two equivalent Se(3) atoms to form HoSe6 octahedra that share corners with three equivalent Ho(1)Se6 octahedra, corners with four equivalent Yb(1)Se7 pentagonal bipyramids, edges with two equivalent Ho(1)Se6 octahedra, edges with two equivalent Ho(2)Se6 octahedra, and edges with four equivalent Yb(1)Se7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 51-59°. The Ho(2)-Se(2) bond length is 2.84 Å. The Ho(2)-Se(4) bond length is 2.88 Å. Both Ho(2)-Se(1) bond lengths are 2.85 Å. Both Ho(2)-Se(3) bond lengths are 2.81 Å. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Yb(1), one Ho(1), and two equivalent Ho(2) atoms to form distorted SeYb2Ho3 trigonal bipyramids that share corners with two equivalent Se(2)Yb2Ho3 square pyramids, corners with six equivalent Se(3)Yb3Ho2 square pyramids, edges with two equivalent Se(3)Yb3Ho2 square pyramids, edges with three equivalent Se(2)Yb2Ho3 square pyramids, and edges with two equivalent Se(1)Yb2Ho3 trigonal bipyramids. In the second Se site, Se(2) is bonded to two equivalent Yb(1), one Ho(2), and two equivalent Ho(1) atoms to form SeYb2Ho3 square pyramids that share corners with two equivalent Se(3)Yb3Ho2 square pyramids, corners with two equivalent Se(1)Yb2Ho3 trigonal bipyramids, edges with two equivalent Se(2)Yb2Ho3 square pyramids, edges with three equivalent Se(3)Yb3Ho2 square pyramids, and edges with three equivalent Se(1)Yb2Ho3 trigonal bipyramids. In the third Se site, Se(3) is bonded to three equivalent Yb(1) and two equivalent Ho(2) atoms to form SeYb3Ho2 square pyramids that share corners with two equivalent Se(2)Yb2Ho3 square pyramids, corners with six equivalent Se(1)Yb2Ho3 trigonal bipyramids, edges with three equivalent Se(2)Yb2Ho3 square pyramids, edges with four equivalent Se(3)Yb3Ho2 square pyramids, and edges with two equivalent Se(1)Yb2Ho3 trigonal bipyramids. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Ho(2) and three equivalent Ho(1) atoms.