Ni4(PO4)3 crystallizes in the tetragonal I-42d space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, edges with two equivalent Ni(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 58°. In the second Ni site, Ni(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 58°. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-47°. In the second P site, P(2) is bonded to four equivalent O(1) atoms to form PO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra and corners with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. There are three inequivalent O sites. In the first O site, O(3) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(2), and one P(1) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(2), and one P(2) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(2), and one P(1) atom.
Ni4(PO4)3 crystallizes in the tetragonal I-42d space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, edges with two equivalent Ni(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 58°. Both Ni(1)-O(1) bond lengths are 2.02 Å. Both Ni(1)-O(2) bond lengths are 2.02 Å. Both Ni(1)-O(3) bond lengths are 2.10 Å. In the second Ni site, Ni(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 58°. Both Ni(2)-O(1) bond lengths are 2.09 Å. Both Ni(2)-O(2) bond lengths are 2.06 Å. Both Ni(2)-O(3) bond lengths are 2.14 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-47°. Both P(1)-O(2) bond lengths are 1.57 Å. Both P(1)-O(3) bond lengths are 1.55 Å. In the second P site, P(2) is bonded to four equivalent O(1) atoms to form PO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra and corners with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. All P(2)-O(1) bond lengths are 1.55 Å. There are three inequivalent O sites. In the first O site, O(3) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(2), and one P(1) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(2), and one P(2) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(2), and one P(1) atom.