Ho2CaGe4O12 crystallizes in the orthorhombic Cmme space group. Ca(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CaO6 octahedra that share corners with eight equivalent Ge(1)O4 tetrahedra. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form HoO6 octahedra that share corners with eight equivalent Ge(1)O4 tetrahedra. In the second Ho site, Ho(2) is bonded in a 8-coordinate geometry to four equivalent O(3) and four equivalent O(4) atoms. Ge(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form GeO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Ho(1)O6 octahedra, and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-71°. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ho(2), and one Ge(1) atom. In the second O site, O(4) is bonded in a distorted trigonal planar geometry to one Ho(1), one Ho(2), and one Ge(1) atom. In the third O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1) and two equivalent Ge(1) atoms. In the fourth O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Ho(1) and two equivalent Ge(1) atoms.
Ho2CaGe4O12 crystallizes in the orthorhombic Cmme space group. Ca(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CaO6 octahedra that share corners with eight equivalent Ge(1)O4 tetrahedra. Both Ca(1)-O(1) bond lengths are 2.57 Å. All Ca(1)-O(3) bond lengths are 2.29 Å. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form HoO6 octahedra that share corners with eight equivalent Ge(1)O4 tetrahedra. Both Ho(1)-O(2) bond lengths are 2.45 Å. All Ho(1)-O(4) bond lengths are 2.21 Å. In the second Ho site, Ho(2) is bonded in a 8-coordinate geometry to four equivalent O(3) and four equivalent O(4) atoms. All Ho(2)-O(3) bond lengths are 2.34 Å. All Ho(2)-O(4) bond lengths are 2.42 Å. Ge(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form GeO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Ho(1)O6 octahedra, and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-71°. The Ge(1)-O(1) bond length is 1.82 Å. The Ge(1)-O(2) bond length is 1.85 Å. The Ge(1)-O(3) bond length is 1.73 Å. The Ge(1)-O(4) bond length is 1.75 Å. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ho(2), and one Ge(1) atom. In the second O site, O(4) is bonded in a distorted trigonal planar geometry to one Ho(1), one Ho(2), and one Ge(1) atom. In the third O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1) and two equivalent Ge(1) atoms. In the fourth O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Ho(1) and two equivalent Ge(1) atoms.