Ni(PO3)4 crystallizes in the monoclinic C2/c space group. Ni(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-49°. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ni(1) and one P(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one P(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Ni(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Ni(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.
Ni(PO3)4 crystallizes in the monoclinic C2/c space group. Ni(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. Both Ni(1)-O(1) bond lengths are 2.08 Å. Both Ni(1)-O(3) bond lengths are 1.95 Å. Both Ni(1)-O(4) bond lengths are 1.97 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 31-49°. The P(1)-O(1) bond length is 1.48 Å. The P(1)-O(3) bond length is 1.52 Å. The P(1)-O(5) bond length is 1.61 Å. The P(1)-O(6) bond length is 1.61 Å. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. The P(2)-O(2) bond length is 1.50 Å. The P(2)-O(4) bond length is 1.52 Å. The P(2)-O(5) bond length is 1.62 Å. The P(2)-O(6) bond length is 1.61 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ni(1) and one P(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one P(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Ni(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Ni(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.