MgNi2(PO5)2 crystallizes in the orthorhombic Fddd space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(3) atoms. 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(1)O6 octahedra and corners with four equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. P(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-61°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ni(1) and one P(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(1) atom.
MgNi2(PO5)2 crystallizes in the orthorhombic Fddd space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(3) atoms. All Mg(1)-O(3) bond lengths are 2.16 Å. 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(1)O6 octahedra and corners with four equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. Both Ni(1)-O(1) bond lengths are 1.90 Å. Both Ni(1)-O(2) bond lengths are 1.81 Å. Both Ni(1)-O(3) bond lengths are 2.20 Å. P(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-61°. Both P(1)-O(1) bond lengths are 1.56 Å. Both P(1)-O(3) bond lengths are 1.55 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ni(1) and one P(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(1) atom.