NaNi2O3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, edges with three equivalent Ni(4)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-11°. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NaO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, edges with three equivalent Ni(3)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with six equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-8°. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, and edges with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-14°. In the third Ni site, Ni(3) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with four equivalent Ni(2)O6 octahedra, and edges with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-14°. In the fourth Ni site, Ni(4) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with four equivalent Ni(2)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-13°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), one Ni(1), one Ni(4), and two equivalent Ni(2) atoms to form a mixture of distorted corner and edge-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the second O site, O(2) is bonded to two equivalent Na(2), one Ni(1), one Ni(3), and two equivalent Ni(2) atoms to form a mixture of corner and edge-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the third O site, O(3) is bonded to two equivalent Na(1), one Ni(1), one Ni(4), and two equivalent Ni(2) atoms to form a mixture of corner and edge-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the fourth O site, O(4) is bonded to two equivalent Na(2), one Ni(1), one Ni(3), and two equivalent Ni(2) atoms to form a mixture of corner and edge-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-10°.
NaNi2O3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, edges with three equivalent Ni(4)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-11°. Both Na(1)-O(1) bond lengths are 2.25 Å. There are two shorter (2.30 Å) and two longer (2.32 Å) Na(1)-O(3) bond lengths. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NaO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, edges with three equivalent Ni(3)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. Both Na(2)-O(2) bond lengths are 2.27 Å. There are two shorter (2.32 Å) and two longer (2.34 Å) Na(2)-O(4) bond lengths. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with six equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-8°. The Ni(1)-O(1) bond length is 2.42 Å. The Ni(1)-O(2) bond length is 2.24 Å. Both Ni(1)-O(3) bond lengths are 1.92 Å. Both Ni(1)-O(4) bond lengths are 1.92 Å. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, and edges with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-14°. The Ni(2)-O(1) bond length is 2.03 Å. The Ni(2)-O(2) bond length is 2.02 Å. There is one shorter (2.09 Å) and one longer (2.15 Å) Ni(2)-O(3) bond length. There is one shorter (2.08 Å) and one longer (2.14 Å) Ni(2)-O(4) bond length. In the third Ni site, Ni(3) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with four equivalent Ni(2)O6 octahedra, and edges with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-14°. Both Ni(3)-O(2) bond lengths are 2.11 Å. All Ni(3)-O(4) bond lengths are 2.17 Å. In the fourth Ni site, Ni(4) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with four equivalent Ni(2)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-13°. Both Ni(4)-O(1) bond lengths are 2.00 Å. All Ni(4)-O(3) bond lengths are 2.15 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), one Ni(1), one Ni(4), and two equivalent Ni(2) atoms to form a mixture of distorted corner and edge-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the second O site, O(2) is bonded to two equivalent Na(2), one Ni(1), one Ni(3), and two equivalent Ni(2) atoms to form a mixture of corner and edge-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the third O site, O(3) is bonded to two equivalent Na(1), one Ni(1), one Ni(4), and two equivalent Ni(2) atoms to form a mixture of corner and edge-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. In the fourth O site, O(4) is bonded to two equivalent Na(2), one Ni(1), one Ni(3), and two equivalent Ni(2) atoms to form a mixture of corner and edge-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-10°.