Na2TiNiO4 is Caswellsilverite-derived structured and crystallizes in the monoclinic P2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-14°. In the second Na site, Na(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NaO6 octahedra that share corners with six equivalent Ti(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. Ti(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with six equivalent Na(2)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. Ni(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NiO6 octahedra that share corners with six equivalent Na(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-14°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), one Ti(1), and two equivalent Ni(1) atoms to form ONa3TiNi2 octahedra that share corners with six equivalent O(1)Na3TiNi2 octahedra, edges with four equivalent O(1)Na3TiNi2 octahedra, and edges with eight equivalent O(2)Na3Ti2Ni octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Na(1), two equivalent Na(2), two equivalent Ti(1), and one Ni(1) atom to form ONa3Ti2Ni octahedra that share corners with six equivalent O(2)Na3Ti2Ni octahedra, edges with four equivalent O(2)Na3Ti2Ni octahedra, and edges with eight equivalent O(1)Na3TiNi2 octahedra. The corner-sharing octahedra are not tilted.
Na2TiNiO4 is Caswellsilverite-derived structured and crystallizes in the monoclinic P2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-14°. Both Na(1)-O(2) bond lengths are 2.31 Å. All Na(1)-O(1) bond lengths are 2.35 Å. In the second Na site, Na(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NaO6 octahedra that share corners with six equivalent Ti(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. Both Na(2)-O(1) bond lengths are 2.48 Å. All Na(2)-O(2) bond lengths are 2.41 Å. Ti(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with six equivalent Na(2)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-10°. Both Ti(1)-O(1) bond lengths are 1.96 Å. All Ti(1)-O(2) bond lengths are 2.03 Å. Ni(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NiO6 octahedra that share corners with six equivalent Na(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-14°. Both Ni(1)-O(2) bond lengths are 2.15 Å. All Ni(1)-O(1) bond lengths are 2.10 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), two equivalent Na(1), one Ti(1), and two equivalent Ni(1) atoms to form ONa3TiNi2 octahedra that share corners with six equivalent O(1)Na3TiNi2 octahedra, edges with four equivalent O(1)Na3TiNi2 octahedra, and edges with eight equivalent O(2)Na3Ti2Ni octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Na(1), two equivalent Na(2), two equivalent Ti(1), and one Ni(1) atom to form ONa3Ti2Ni octahedra that share corners with six equivalent O(2)Na3Ti2Ni octahedra, edges with four equivalent O(2)Na3Ti2Ni octahedra, and edges with eight equivalent O(1)Na3TiNi2 octahedra. The corner-sharing octahedra are not tilted.