K3NiCPO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(6) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. Ni(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form NiO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. P(1) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-42°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(1), two equivalent K(2), and one C(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Ni(1), and one C(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Ni(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to four equivalent K(2), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to four equivalent K(2), one Ni(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Ni(1), and one P(1) atom.
K3NiCPO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(6) atoms. The K(1)-O(2) bond length is 2.72 Å. The K(1)-O(3) bond length is 2.76 Å. There is one shorter (2.81 Å) and one longer (2.84 Å) K(1)-O(1) bond length. Both K(1)-O(6) bond lengths are 2.73 Å. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. The K(2)-O(1) bond length is 2.85 Å. The K(2)-O(2) bond length is 2.84 Å. The K(2)-O(3) bond length is 2.78 Å. There is one shorter (2.91 Å) and one longer (2.98 Å) K(2)-O(4) bond length. There is one shorter (2.74 Å) and one longer (3.22 Å) K(2)-O(5) bond length. There is one shorter (2.85 Å) and one longer (2.87 Å) K(2)-O(6) bond length. Ni(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form NiO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra. The Ni(1)-O(2) bond length is 2.13 Å. The Ni(1)-O(3) bond length is 2.14 Å. The Ni(1)-O(4) bond length is 2.05 Å. The Ni(1)-O(5) bond length is 2.05 Å. Both Ni(1)-O(6) bond lengths are 2.20 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.29 Å. The C(1)-O(2) bond length is 1.31 Å. The C(1)-O(3) bond length is 1.31 Å. P(1) is bonded to one O(4), one O(5), and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-42°. The P(1)-O(4) bond length is 1.56 Å. The P(1)-O(5) bond length is 1.55 Å. Both P(1)-O(6) bond lengths are 1.56 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(1), two equivalent K(2), and one C(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Ni(1), and one C(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Ni(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to four equivalent K(2), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to four equivalent K(2), one Ni(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Ni(1), and one P(1) atom.