Na2NiCPO7 crystallizes in the monoclinic Pc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. In the third Na site, Na(3) is bonded to one O(10), one O(11), one O(12), one O(13), one O(14), one O(8), and one O(9) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one P(2)O4 tetrahedra, and  a faceface with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 64°. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(2), one O(3), and two equivalent O(14) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Na(3)O7 pentagonal bipyramid, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. In the second Ni site, Ni(2) is bonded to one O(10), one O(11), one O(12), one O(13), one O(7), and one O(9) atom to form NiO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Na(3)O7 pentagonal bipyramid, and  a faceface with one Na(3)O7 pentagonal bipyramid. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(14), one O(2), and one O(3) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(1), one O(12), and one O(13) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, and  a cornercorner with one Na(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 37-50°. In the second P site, P(2) is bonded to one O(10), one O(11), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one Na(3)O7 pentagonal bipyramid, and  an edgeedge with one Na(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-48°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one C(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Ni(1), and one C(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1), one Na(2), one Na(4), one Ni(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 3-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 one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Ni(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(2), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(3), one Ni(1), and one P(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(3), one Ni(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Ni(2), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Ni(2), and one P(2) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Na(3), one Ni(2), and one C(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(3), one Ni(2), and one C(2) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(3), two equivalent Na(4), and one C(1) atom.
Na2NiCPO7 crystallizes in the monoclinic Pc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The Na(1)-O(1) bond length is 2.34 Å. The Na(1)-O(2) bond length is 2.64 Å. The Na(1)-O(3) bond length is 2.36 Å. The Na(1)-O(4) bond length is 2.92 Å. The Na(1)-O(5) bond length is 2.46 Å. The Na(1)-O(6) bond length is 2.38 Å. The Na(1)-O(7) bond length is 2.51 Å. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The Na(2)-O(1) bond length is 2.34 Å. The Na(2)-O(2) bond length is 2.67 Å. The Na(2)-O(3) bond length is 2.37 Å. The Na(2)-O(4) bond length is 2.45 Å. The Na(2)-O(5) bond length is 2.88 Å. The Na(2)-O(6) bond length is 2.35 Å. The Na(2)-O(7) bond length is 2.52 Å. In the third Na site, Na(3) is bonded to one O(10), one O(11), one O(12), one O(13), one O(14), one O(8), and one O(9) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one P(2)O4 tetrahedra, and  a faceface with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 64°. The Na(3)-O(10) bond length is 2.69 Å. The Na(3)-O(11) bond length is 2.45 Å. The Na(3)-O(12) bond length is 2.38 Å. The Na(3)-O(13) bond length is 2.66 Å. The Na(3)-O(14) bond length is 2.30 Å. The Na(3)-O(8) bond length is 2.47 Å. The Na(3)-O(9) bond length is 2.33 Å. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(2), one O(3), and two equivalent O(14) atoms. The Na(4)-O(10) bond length is 2.42 Å. The Na(4)-O(11) bond length is 2.45 Å. The Na(4)-O(2) bond length is 2.43 Å. The Na(4)-O(3) bond length is 2.84 Å. There is one shorter (2.49 Å) and one longer (2.72 Å) Na(4)-O(14) bond length. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Na(3)O7 pentagonal bipyramid, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The Ni(1)-O(2) bond length is 2.08 Å. The Ni(1)-O(3) bond length is 2.15 Å. The Ni(1)-O(4) bond length is 2.03 Å. The Ni(1)-O(5) bond length is 2.05 Å. The Ni(1)-O(6) bond length is 2.04 Å. The Ni(1)-O(8) bond length is 1.97 Å. In the second Ni site, Ni(2) is bonded to one O(10), one O(11), one O(12), one O(13), one O(7), and one O(9) atom to form NiO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Na(3)O7 pentagonal bipyramid, and  a faceface with one Na(3)O7 pentagonal bipyramid. The Ni(2)-O(10) bond length is 2.04 Å. The Ni(2)-O(11) bond length is 2.05 Å. The Ni(2)-O(12) bond length is 2.05 Å. The Ni(2)-O(13) bond length is 2.07 Å. The Ni(2)-O(7) bond length is 2.04 Å. The Ni(2)-O(9) bond length is 2.01 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(14), one O(2), and one O(3) atom. The C(1)-O(14) bond length is 1.26 Å. The C(1)-O(2) bond length is 1.31 Å. The C(1)-O(3) bond length is 1.31 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(1), one O(12), and one O(13) atom. The C(2)-O(1) bond length is 1.27 Å. The C(2)-O(12) bond length is 1.31 Å. The C(2)-O(13) bond length is 1.30 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, and  a cornercorner with one Na(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 37-50°. The P(1)-O(4) bond length is 1.55 Å. The P(1)-O(5) bond length is 1.56 Å. The P(1)-O(7) bond length is 1.57 Å. The P(1)-O(9) bond length is 1.54 Å. In the second P site, P(2) is bonded to one O(10), one O(11), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one Na(3)O7 pentagonal bipyramid, and  an edgeedge with one Na(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-48°. The P(2)-O(10) bond length is 1.55 Å. The P(2)-O(11) bond length is 1.55 Å. The P(2)-O(6) bond length is 1.54 Å. The P(2)-O(8) bond length is 1.57 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one C(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Ni(1), and one C(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1), one Na(2), one Na(4), one Ni(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 3-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 one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Ni(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(2), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(3), one Ni(1), and one P(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(3), one Ni(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Ni(2), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Ni(2), and one P(2) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Na(3), one Ni(2), and one C(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(3), one Ni(2), and one C(2) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(3), two equivalent Na(4), and one C(1) atom.