Na2NiO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 15-18°. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-19°. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, edges with three equivalent Ni(2)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-19°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, edges with three equivalent Ni(2)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-15°. In the second Ni site, Ni(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-15°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Ni(1), and one Ni(2) atom to form a mixture of distorted corner and edge-sharing ONa4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-12°. In the second O site, O(2) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Ni(1), and one Ni(2) atom to form a mixture of distorted corner and edge-sharing ONa4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the third O site, O(3) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Ni(1), and one Ni(2) atom to form a mixture of distorted corner and edge-sharing ONa4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°.
Na2NiO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 15-18°. There is one shorter (2.39 Å) and one longer (2.41 Å) Na(1)-O(1) bond length. There is one shorter (2.25 Å) and one longer (2.48 Å) Na(1)-O(2) bond length. There is one shorter (2.24 Å) and one longer (2.48 Å) Na(1)-O(3) bond length. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-19°. Both Na(2)-O(1) bond lengths are 2.21 Å. Both Na(2)-O(2) bond lengths are 2.45 Å. Both Na(2)-O(3) bond lengths are 2.47 Å. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, edges with three equivalent Ni(2)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-19°. Both Na(3)-O(1) bond lengths are 2.22 Å. Both Na(3)-O(2) bond lengths are 2.22 Å. Both Na(3)-O(3) bond lengths are 2.23 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, edges with three equivalent Ni(2)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-15°. Both Ni(1)-O(1) bond lengths are 1.93 Å. Both Ni(1)-O(2) bond lengths are 1.94 Å. Both Ni(1)-O(3) bond lengths are 1.93 Å. In the second Ni site, Ni(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-15°. Both Ni(2)-O(1) bond lengths are 1.94 Å. Both Ni(2)-O(2) bond lengths are 1.93 Å. Both Ni(2)-O(3) bond lengths are 1.93 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Ni(1), and one Ni(2) atom to form a mixture of distorted corner and edge-sharing ONa4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-12°. In the second O site, O(2) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Ni(1), and one Ni(2) atom to form a mixture of distorted corner and edge-sharing ONa4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the third O site, O(3) is bonded to one Na(2), one Na(3), two equivalent Na(1), one Ni(1), and one Ni(2) atom to form a mixture of distorted corner and edge-sharing ONa4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°.