NaMnO2 crystallizes in the orthorhombic Pmmn space group. Na(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, edges with six equivalent Na(1)O6 octahedra, and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. 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 Mn(1)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with six equivalent Na(1)O6 octahedra, and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-13°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1) and four equivalent Mn(1) atoms to form distorted ONa2Mn4 octahedra that share corners with two equivalent O(1)Na2Mn4 octahedra, corners with four equivalent O(2)Na4Mn2 octahedra, edges with six equivalent O(1)Na2Mn4 octahedra, and edges with six equivalent O(2)Na4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second O site, O(2) is bonded to four equivalent Na(1) and two equivalent Mn(1) atoms to form ONa4Mn2 octahedra that share corners with two equivalent O(2)Na4Mn2 octahedra, corners with four equivalent O(1)Na2Mn4 octahedra, edges with six equivalent O(1)Na2Mn4 octahedra, and edges with six equivalent O(2)Na4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-14°.
NaMnO2 crystallizes in the orthorhombic Pmmn space group. Na(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, edges with six equivalent Na(1)O6 octahedra, and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. Both Na(1)-O(1) bond lengths are 2.33 Å. There are two shorter (2.34 Å) and two longer (2.41 Å) Na(1)-O(2) bond lengths. 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 Mn(1)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with six equivalent Na(1)O6 octahedra, and edges with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-13°. Both Mn(1)-O(2) bond lengths are 1.92 Å. There are two shorter (1.94 Å) and two longer (2.41 Å) Mn(1)-O(1) bond lengths. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1) and four equivalent Mn(1) atoms to form distorted ONa2Mn4 octahedra that share corners with two equivalent O(1)Na2Mn4 octahedra, corners with four equivalent O(2)Na4Mn2 octahedra, edges with six equivalent O(1)Na2Mn4 octahedra, and edges with six equivalent O(2)Na4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second O site, O(2) is bonded to four equivalent Na(1) and two equivalent Mn(1) atoms to form ONa4Mn2 octahedra that share corners with two equivalent O(2)Na4Mn2 octahedra, corners with four equivalent O(1)Na2Mn4 octahedra, edges with six equivalent O(1)Na2Mn4 octahedra, and edges with six equivalent O(2)Na4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-14°.