Na2MnO2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted trigonal planar geometry to one O(1) and two equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a distorted trigonal planar geometry to one O(2) and two equivalent O(1) atoms. Mn(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and two equivalent Mn(1) atoms to form a mixture of distorted edge and corner-sharing ONa3Mn2 trigonal bipyramids. In the second O site, O(2) is bonded to one Na(2), two equivalent Na(1), and two equivalent Mn(1) atoms to form a mixture of distorted edge and corner-sharing ONa3Mn2 trigonal bipyramids.
Na2MnO2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted trigonal planar geometry to one O(1) and two equivalent O(2) atoms. The Na(1)-O(1) bond length is 2.29 Å. There is one shorter (2.32 Å) and one longer (2.46 Å) Na(1)-O(2) bond length. In the second Na site, Na(2) is bonded in a distorted trigonal planar geometry to one O(2) and two equivalent O(1) atoms. The Na(2)-O(2) bond length is 2.30 Å. There is one shorter (2.29 Å) and one longer (2.47 Å) Na(2)-O(1) bond length. Mn(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Mn(1)-O(1) bond lengths are 2.09 Å. Both Mn(1)-O(2) bond lengths are 2.10 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), and two equivalent Mn(1) atoms to form a mixture of distorted edge and corner-sharing ONa3Mn2 trigonal bipyramids. In the second O site, O(2) is bonded to one Na(2), two equivalent Na(1), and two equivalent Mn(1) atoms to form a mixture of distorted edge and corner-sharing ONa3Mn2 trigonal bipyramids.