CaNi2(PO4)2 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(8) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form NiO5 square pyramids that share corners with two equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. In the second Ni site, Ni(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. In the third Ni site, Ni(3) is bonded in a 6-coordinate geometry to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O5 square pyramids. In the second P site, P(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Ni(1)O5 square pyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ni(2), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Ni(1), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Ni(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Ni(1), one Ni(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ca(1), one Ni(3), and one P(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Ca(1), one Ni(1), one Ni(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(3), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one P(1) atom.
CaNi2(PO4)2 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(8) atoms. The Ca(1)-O(1) bond length is 2.37 Å. The Ca(1)-O(2) bond length is 2.42 Å. The Ca(1)-O(3) bond length is 2.66 Å. The Ca(1)-O(4) bond length is 2.66 Å. The Ca(1)-O(5) bond length is 2.80 Å. The Ca(1)-O(6) bond length is 2.52 Å. There is one shorter (2.27 Å) and one longer (2.56 Å) Ca(1)-O(8) bond length. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form NiO5 square pyramids that share corners with two equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. The Ni(1)-O(2) bond length is 2.00 Å. The Ni(1)-O(3) bond length is 2.09 Å. The Ni(1)-O(4) bond length is 2.07 Å. The Ni(1)-O(6) bond length is 2.07 Å. The Ni(1)-O(7) bond length is 2.02 Å. In the second Ni site, Ni(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(4) atoms. Both Ni(2)-O(1) bond lengths are 2.00 Å. Both Ni(2)-O(4) bond lengths are 2.00 Å. In the third Ni site, Ni(3) is bonded in a 6-coordinate geometry to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. Both Ni(3)-O(5) bond lengths are 2.02 Å. Both Ni(3)-O(6) bond lengths are 2.47 Å. Both Ni(3)-O(7) bond lengths are 2.05 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O5 square pyramids. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(4) bond length is 1.58 Å. The P(1)-O(7) bond length is 1.56 Å. The P(1)-O(8) bond length is 1.52 Å. In the second P site, P(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Ni(1)O5 square pyramids. The P(2)-O(2) bond length is 1.56 Å. The P(2)-O(3) bond length is 1.57 Å. The P(2)-O(5) bond length is 1.53 Å. The P(2)-O(6) bond length is 1.57 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ni(2), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Ni(1), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Ni(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Ni(1), one Ni(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ca(1), one Ni(3), and one P(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Ca(1), one Ni(1), one Ni(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(3), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one P(1) atom.