Na2MnO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three 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 two equivalent Na(3)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with four equivalent Mn(1)O6 octahedra, and edges with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-17°. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-17°. In the third Na site, Na(3) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 17°. Mn(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MnO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and edges with four equivalent Na(2)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(1), one Na(3), two equivalent Na(2), and two equivalent Mn(1) atoms to form a mixture of distorted corner and edge-sharing ONa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second O site, O(2) is bonded to one Na(1), one Na(3), two equivalent Na(2), and two equivalent Mn(1) atoms to form a mixture of corner and edge-sharing ONa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°.
Na2MnO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three 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 two equivalent Na(3)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with four equivalent Mn(1)O6 octahedra, and edges with six equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-17°. Both Na(1)-O(2) bond lengths are 2.20 Å. All Na(1)-O(1) bond lengths are 2.42 Å. In the second Na site, Na(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-17°. Both Na(2)-O(2) bond lengths are 2.37 Å. There are two shorter (2.23 Å) and two longer (2.45 Å) Na(2)-O(1) bond lengths. In the third Na site, Na(3) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 17°. Both Na(3)-O(2) bond lengths are 2.21 Å. All Na(3)-O(1) bond lengths are 2.21 Å. Mn(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MnO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with three equivalent Na(3)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and edges with four equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-14°. Both Mn(1)-O(2) bond lengths are 1.95 Å. All Mn(1)-O(1) bond lengths are 1.94 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), two equivalent Na(2), and two equivalent Mn(1) atoms to form a mixture of distorted corner and edge-sharing ONa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second O site, O(2) is bonded to one Na(1), one Na(3), two equivalent Na(2), and two equivalent Mn(1) atoms to form a mixture of corner and edge-sharing ONa4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°.