Ho2P4O13 crystallizes in the orthorhombic C222_1 space group. Ho(1) is bonded to one O(3), one O(5), one O(7), two equivalent O(2), and two equivalent O(4) atoms to form distorted HoO7 pentagonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, edges with two equivalent Ho(1)O7 pentagonal bipyramids, and  an edgeedge with one P(1)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Ho(1)O7 pentagonal bipyramids,  a cornercorner with one P(2)O4 tetrahedra, and  an edgeedge with one Ho(1)O7 pentagonal bipyramid. In the second P site, P(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Ho(1)O7 pentagonal bipyramids,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(7) is bonded in a linear geometry to one Ho(1) and one P(2) atom. In the third O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent P(2) atoms. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ho(1) and one P(1) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Ho(1) and one P(1) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ho(1) and one P(1) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Ho(1) and one P(2) atom.
Ho2P4O13 crystallizes in the orthorhombic C222_1 space group. Ho(1) is bonded to one O(3), one O(5), one O(7), two equivalent O(2), and two equivalent O(4) atoms to form distorted HoO7 pentagonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, edges with two equivalent Ho(1)O7 pentagonal bipyramids, and  an edgeedge with one P(1)O4 tetrahedra. The Ho(1)-O(3) bond length is 2.19 Å. The Ho(1)-O(5) bond length is 2.21 Å. The Ho(1)-O(7) bond length is 2.22 Å. There is one shorter (2.33 Å) and one longer (2.50 Å) Ho(1)-O(2) bond length. There is one shorter (2.31 Å) and one longer (2.35 Å) Ho(1)-O(4) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Ho(1)O7 pentagonal bipyramids,  a cornercorner with one P(2)O4 tetrahedra, and  an edgeedge with one Ho(1)O7 pentagonal bipyramid. The P(1)-O(2) bond length is 1.53 Å. The P(1)-O(3) bond length is 1.49 Å. The P(1)-O(4) bond length is 1.52 Å. The P(1)-O(6) bond length is 1.61 Å. In the second P site, P(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Ho(1)O7 pentagonal bipyramids,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The P(2)-O(1) bond length is 1.57 Å. The P(2)-O(5) bond length is 1.49 Å. The P(2)-O(6) bond length is 1.58 Å. The P(2)-O(7) bond length is 1.48 Å. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(7) is bonded in a linear geometry to one Ho(1) and one P(2) atom. In the third O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent P(2) atoms. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ho(1) and one P(1) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Ho(1) and one P(1) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ho(1) and one P(1) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Ho(1) and one P(2) atom.