Na3MnO3 crystallizes in the triclinic P-1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO5 trigonal bipyramids that share corners with three equivalent Mn(1)O4 tetrahedra, corners with two equivalent Na(2)O4 trigonal pyramids, edges with two equivalent Mn(1)O4 tetrahedra, edges with two equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Na(2)O4 trigonal pyramids. In the second Na site, Na(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form NaO4 trigonal pyramids that share corners with five equivalent Mn(1)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, edges with two equivalent Na(1)O5 trigonal bipyramids, and  an edgeedge with one Na(2)O4 trigonal pyramid. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(1) atoms. Mn(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form MnO4 tetrahedra that share corners with three equivalent Na(1)O5 trigonal bipyramids, corners with five equivalent Na(2)O4 trigonal pyramids,  an edgeedge with one Mn(1)O4 tetrahedra, and edges with two equivalent Na(1)O5 trigonal bipyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), two equivalent Na(2), two equivalent Na(3), and one Mn(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), and one Mn(1) atom. In the third O site, O(3) is bonded to one Na(2), one Na(3), two equivalent Na(1), and two equivalent Mn(1) atoms to form distorted edge-sharing ONa4Mn2 octahedra.
Na3MnO3 crystallizes in the triclinic P-1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO5 trigonal bipyramids that share corners with three equivalent Mn(1)O4 tetrahedra, corners with two equivalent Na(2)O4 trigonal pyramids, edges with two equivalent Mn(1)O4 tetrahedra, edges with two equivalent Na(1)O5 trigonal bipyramids, and edges with two equivalent Na(2)O4 trigonal pyramids. The Na(1)-O(1) bond length is 2.57 Å. Both Na(1)-O(2) bond lengths are 2.37 Å. There is one shorter (2.42 Å) and one longer (2.66 Å) Na(1)-O(3) bond length. In the second Na site, Na(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form NaO4 trigonal pyramids that share corners with five equivalent Mn(1)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids, edges with two equivalent Na(1)O5 trigonal bipyramids, and  an edgeedge with one Na(2)O4 trigonal pyramid. The Na(2)-O(2) bond length is 2.31 Å. The Na(2)-O(3) bond length is 2.31 Å. There is one shorter (2.28 Å) and one longer (2.53 Å) Na(2)-O(1) bond length. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(1) atoms. The Na(3)-O(2) bond length is 2.42 Å. The Na(3)-O(3) bond length is 2.39 Å. There is one shorter (2.31 Å) and one longer (2.52 Å) Na(3)-O(1) bond length. Mn(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form MnO4 tetrahedra that share corners with three equivalent Na(1)O5 trigonal bipyramids, corners with five equivalent Na(2)O4 trigonal pyramids,  an edgeedge with one Mn(1)O4 tetrahedra, and edges with two equivalent Na(1)O5 trigonal bipyramids. The Mn(1)-O(1) bond length is 1.87 Å. The Mn(1)-O(2) bond length is 1.87 Å. There is one shorter (1.92 Å) and one longer (2.10 Å) Mn(1)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), two equivalent Na(2), two equivalent Na(3), and one Mn(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), and one Mn(1) atom. In the third O site, O(3) is bonded to one Na(2), one Na(3), two equivalent Na(1), and two equivalent Mn(1) atoms to form distorted edge-sharing ONa4Mn2 octahedra.