Na3NiCPO7 crystallizes in the monoclinic P2_1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted NaO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(6) atom. In the third Na site, Na(3) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted NaO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra and faces with two equivalent Na(3)O6 octahedra. Ni(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(5) atom. P(1) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra and corners with four equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-71°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Ni(1), and one C(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Ni(1), and one C(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Ni(1), and one C(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Na(3), and one P(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Ni(1), and one P(1) atom.
Na3NiCPO7 crystallizes in the monoclinic P2_1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted NaO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. The Na(1)-O(3) bond length is 2.33 Å. The Na(1)-O(4) bond length is 2.32 Å. Both Na(1)-O(1) bond lengths are 2.45 Å. Both Na(1)-O(2) bond lengths are 2.41 Å. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(6) atom. The Na(2)-O(1) bond length is 2.34 Å. The Na(2)-O(2) bond length is 2.69 Å. The Na(2)-O(3) bond length is 2.40 Å. The Na(2)-O(4) bond length is 2.44 Å. The Na(2)-O(6) bond length is 2.23 Å. In the third Na site, Na(3) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted NaO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra and faces with two equivalent Na(3)O6 octahedra. There is one shorter (2.41 Å) and one longer (2.42 Å) Na(3)-O(5) bond length. There is one shorter (2.29 Å) and one longer (2.31 Å) Na(3)-O(6) bond length. There is one shorter (2.66 Å) and one longer (2.67 Å) Na(3)-O(7) bond length. Ni(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom. The Ni(1)-O(1) bond length is 2.46 Å. The Ni(1)-O(2) bond length is 2.24 Å. The Ni(1)-O(3) bond length is 2.07 Å. The Ni(1)-O(4) bond length is 2.08 Å. The Ni(1)-O(5) bond length is 2.08 Å. The Ni(1)-O(7) bond length is 2.01 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(5) atom. The C(1)-O(1) bond length is 1.31 Å. The C(1)-O(2) bond length is 1.31 Å. The C(1)-O(5) bond length is 1.29 Å. P(1) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra and corners with four equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-71°. The P(1)-O(3) bond length is 1.57 Å. The P(1)-O(4) bond length is 1.57 Å. The P(1)-O(6) bond length is 1.54 Å. The P(1)-O(7) bond length is 1.56 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Ni(1), and one C(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(1), one Ni(1), and one C(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Ni(1), and one C(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Na(3), and one P(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Ni(1), and one P(1) atom.