Na4Ni7(PO4)6 crystallizes in the monoclinic Cm space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent O(11), two equivalent O(14), and two equivalent O(7) atoms. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(5), and two equivalent O(8) atoms. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(1), one O(12), one O(13), and one O(7) atom. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(10), one O(11), one O(13), one O(5), one O(8), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra, and  an edgeedge with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-68°. In the second Ni site, Ni(2) is bonded to one O(10), one O(12), one O(14), one O(6), one O(7), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-69°. In the third Ni site, Ni(3) is bonded to one O(1), one O(12), one O(13), one O(2), one O(5), and one O(6) atom to form distorted NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-69°. In the fourth Ni site, Ni(4) is bonded to one O(3), one O(4), two equivalent O(11), and two equivalent O(14) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-60°. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), and two equivalent O(6) atoms to form PO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. In the second P site, P(2) is bonded to one O(2), one O(4), and two equivalent O(5) atoms to form PO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-54°. In the third P site, P(3) is bonded to one O(10), one O(12), one O(14), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, and  an edgeedge with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-60°. In the fourth P site, P(4) is bonded to one O(11), one O(13), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-62°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Na(3), two equivalent Ni(3), and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Ni(3) and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ni(4) and one P(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Na(2), one Ni(4), and one P(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(2), one Ni(1), one Ni(3), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ni(2), one Ni(3), and one P(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Ni(2), and one P(4) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Ni(1), and one P(3) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(2), and one P(4) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(2), and one P(3) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(1), one Ni(1), one Ni(4), and one P(4) atom. In the twelfth O site, O(12) is bonded to one Na(3), one Ni(2), one Ni(3), and one P(3) atom to form distorted corner-sharing ONaNi2P tetrahedra. In the thirteenth O site, O(13) is bonded to one Na(3), one Ni(1), one Ni(3), and one P(4) atom to form distorted corner-sharing ONaNi2P trigonal pyramids. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(1), one Ni(2), one Ni(4), and one P(3) atom.
Na4Ni7(PO4)6 crystallizes in the monoclinic Cm space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent O(11), two equivalent O(14), and two equivalent O(7) atoms. Both Na(1)-O(11) bond lengths are 2.48 Å. Both Na(1)-O(14) bond lengths are 2.52 Å. Both Na(1)-O(7) bond lengths are 2.63 Å. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(5), and two equivalent O(8) atoms. The Na(2)-O(4) bond length is 2.43 Å. Both Na(2)-O(5) bond lengths are 2.57 Å. Both Na(2)-O(8) bond lengths are 2.64 Å. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(1), one O(12), one O(13), and one O(7) atom. The Na(3)-O(1) bond length is 2.60 Å. The Na(3)-O(12) bond length is 2.36 Å. The Na(3)-O(13) bond length is 2.43 Å. The Na(3)-O(7) bond length is 2.52 Å. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(10), one O(11), one O(13), one O(5), one O(8), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra, and  an edgeedge with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-68°. The Ni(1)-O(10) bond length is 2.05 Å. The Ni(1)-O(11) bond length is 2.08 Å. The Ni(1)-O(13) bond length is 2.20 Å. The Ni(1)-O(5) bond length is 2.03 Å. The Ni(1)-O(8) bond length is 2.02 Å. The Ni(1)-O(9) bond length is 2.09 Å. In the second Ni site, Ni(2) is bonded to one O(10), one O(12), one O(14), one O(6), one O(7), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-69°. The Ni(2)-O(10) bond length is 2.07 Å. The Ni(2)-O(12) bond length is 2.18 Å. The Ni(2)-O(14) bond length is 2.10 Å. The Ni(2)-O(6) bond length is 2.06 Å. The Ni(2)-O(7) bond length is 2.03 Å. The Ni(2)-O(9) bond length is 2.08 Å. In the third Ni site, Ni(3) is bonded to one O(1), one O(12), one O(13), one O(2), one O(5), and one O(6) atom to form distorted NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 59-69°. The Ni(3)-O(1) bond length is 2.38 Å. The Ni(3)-O(12) bond length is 2.09 Å. The Ni(3)-O(13) bond length is 2.11 Å. The Ni(3)-O(2) bond length is 2.32 Å. The Ni(3)-O(5) bond length is 2.04 Å. The Ni(3)-O(6) bond length is 2.04 Å. In the fourth Ni site, Ni(4) is bonded to one O(3), one O(4), two equivalent O(11), and two equivalent O(14) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-60°. The Ni(4)-O(3) bond length is 2.11 Å. The Ni(4)-O(4) bond length is 2.15 Å. Both Ni(4)-O(11) bond lengths are 2.06 Å. Both Ni(4)-O(14) bond lengths are 2.05 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), and two equivalent O(6) atoms to form PO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. The P(1)-O(1) bond length is 1.57 Å. The P(1)-O(3) bond length is 1.52 Å. Both P(1)-O(6) bond lengths are 1.57 Å. In the second P site, P(2) is bonded to one O(2), one O(4), and two equivalent O(5) atoms to form PO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-54°. The P(2)-O(2) bond length is 1.57 Å. The P(2)-O(4) bond length is 1.52 Å. Both P(2)-O(5) bond lengths are 1.58 Å. In the third P site, P(3) is bonded to one O(10), one O(12), one O(14), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, and  an edgeedge with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-60°. The P(3)-O(10) bond length is 1.55 Å. The P(3)-O(12) bond length is 1.59 Å. The P(3)-O(14) bond length is 1.57 Å. The P(3)-O(8) bond length is 1.52 Å. In the fourth P site, P(4) is bonded to one O(11), one O(13), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-62°. The P(4)-O(11) bond length is 1.58 Å. The P(4)-O(13) bond length is 1.58 Å. The P(4)-O(7) bond length is 1.53 Å. The P(4)-O(9) bond length is 1.56 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Na(3), two equivalent Ni(3), and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Ni(3) and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ni(4) and one P(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Na(2), one Ni(4), and one P(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(2), one Ni(1), one Ni(3), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ni(2), one Ni(3), and one P(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Ni(2), and one P(4) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Ni(1), and one P(3) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(2), and one P(4) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ni(1), one Ni(2), and one P(3) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(1), one Ni(1), one Ni(4), and one P(4) atom. In the twelfth O site, O(12) is bonded to one Na(3), one Ni(2), one Ni(3), and one P(3) atom to form distorted corner-sharing ONaNi2P tetrahedra. In the thirteenth O site, O(13) is bonded to one Na(3), one Ni(1), one Ni(3), and one P(4) atom to form distorted corner-sharing ONaNi2P trigonal pyramids. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(1), one Ni(2), one Ni(4), and one P(3) atom.