Ho2Ge2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. In the second Ho site, Ho(2) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form HoO12 cuboctahedra that share corners with four equivalent Ho(2)O12 cuboctahedra, faces with four equivalent Ho(2)O12 cuboctahedra, and faces with eight equivalent Ge(1)O5 square pyramids. Ge(1) is bonded to one O(2) and four equivalent O(1) atoms to form GeO5 square pyramids that share corners with five equivalent Ge(1)O5 square pyramids and faces with four equivalent Ho(2)O12 cuboctahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ho(1), two equivalent Ho(2), and two equivalent Ge(1) atoms to form a mixture of distorted corner, edge, and face-sharing OHo4Ge2 octahedra. The corner-sharing octahedral tilt angles range from 0-69°. In the second O site, O(2) is bonded in a linear geometry to four equivalent Ho(2) and two equivalent Ge(1) atoms.
Ho2Ge2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. All Ho(1)-O(1) bond lengths are 2.56 Å. In the second Ho site, Ho(2) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form HoO12 cuboctahedra that share corners with four equivalent Ho(2)O12 cuboctahedra, faces with four equivalent Ho(2)O12 cuboctahedra, and faces with eight equivalent Ge(1)O5 square pyramids. All Ho(2)-O(2) bond lengths are 2.90 Å. All Ho(2)-O(1) bond lengths are 2.72 Å. Ge(1) is bonded to one O(2) and four equivalent O(1) atoms to form GeO5 square pyramids that share corners with five equivalent Ge(1)O5 square pyramids and faces with four equivalent Ho(2)O12 cuboctahedra. The Ge(1)-O(2) bond length is 1.90 Å. All Ge(1)-O(1) bond lengths are 2.05 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ho(1), two equivalent Ho(2), and two equivalent Ge(1) atoms to form a mixture of distorted corner, edge, and face-sharing OHo4Ge2 octahedra. The corner-sharing octahedral tilt angles range from 0-69°. In the second O site, O(2) is bonded in a linear geometry to four equivalent Ho(2) and two equivalent Ge(1) atoms.