CaNi2(PO5)2 crystallizes in the orthorhombic Fddd space group. Ca(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and 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 69°. 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 44-57°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one Ni(1), and one P(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to two equivalent Ni(1) and one O(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ni(1), and one P(1) atom.
CaNi2(PO5)2 crystallizes in the orthorhombic Fddd space group. Ca(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. All Ca(1)-O(1) bond lengths are 2.50 Å. All Ca(1)-O(3) bond lengths are 2.49 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 69°. Both Ni(1)-O(1) bond lengths are 2.04 Å. Both Ni(1)-O(2) bond lengths are 2.20 Å. Both Ni(1)-O(3) bond lengths are 2.00 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 44-57°. 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 3-coordinate geometry to one Ca(1), one Ni(1), and one P(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to two equivalent Ni(1) and one O(2) atom. The O(2)-O(2) bond length is 1.28 Å. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ni(1), and one P(1) atom.