NaMn3O6 crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(6) atom. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted MnO5 square pyramids that share corners with three equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 47-51°. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O5 square pyramids,  an edgeedge with one Mn(2)O6 octahedra, and edges with three equivalent Mn(3)O6 octahedra. In the third Mn site, Mn(3) is bonded to one O(2), one O(3), one O(4), one O(6), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O5 square pyramids,  an edgeedge with one Mn(3)O6 octahedra, and edges with three equivalent Mn(2)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Mn(2), and two equivalent Mn(1) atoms to form a mixture of corner and edge-sharing ONaMn3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mn(3) and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Na(1), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Mn(1), one Mn(2), and one Mn(3) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Mn(2), and two equivalent Mn(3) atoms. In the sixth O site, O(6) is bonded to one Na(1), one Mn(3), and two equivalent Mn(2) atoms to form a mixture of corner and edge-sharing ONaMn3 trigonal pyramids.
NaMn3O6 crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(6) atom. The Na(1)-O(1) bond length is 2.31 Å. The Na(1)-O(3) bond length is 2.24 Å. The Na(1)-O(4) bond length is 2.79 Å. The Na(1)-O(5) bond length is 2.17 Å. The Na(1)-O(6) bond length is 2.14 Å. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted MnO5 square pyramids that share corners with three equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 47-51°. The Mn(1)-O(4) bond length is 2.31 Å. There is one shorter (1.95 Å) and one longer (1.97 Å) Mn(1)-O(1) bond length. There is one shorter (1.92 Å) and one longer (1.97 Å) Mn(1)-O(2) bond length. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O5 square pyramids,  an edgeedge with one Mn(2)O6 octahedra, and edges with three equivalent Mn(3)O6 octahedra. The Mn(2)-O(1) bond length is 1.99 Å. The Mn(2)-O(3) bond length is 1.89 Å. The Mn(2)-O(4) bond length is 1.93 Å. The Mn(2)-O(5) bond length is 1.97 Å. There is one shorter (1.94 Å) and one longer (2.00 Å) Mn(2)-O(6) bond length. In the third Mn site, Mn(3) is bonded to one O(2), one O(3), one O(4), one O(6), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O5 square pyramids,  an edgeedge with one Mn(3)O6 octahedra, and edges with three equivalent Mn(2)O6 octahedra. The Mn(3)-O(2) bond length is 1.93 Å. The Mn(3)-O(3) bond length is 1.89 Å. The Mn(3)-O(4) bond length is 1.95 Å. The Mn(3)-O(6) bond length is 1.95 Å. There is one shorter (1.95 Å) and one longer (2.03 Å) Mn(3)-O(5) bond length. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Mn(2), and two equivalent Mn(1) atoms to form a mixture of corner and edge-sharing ONaMn3 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mn(3) and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Na(1), one Mn(2), and one Mn(3) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Mn(1), one Mn(2), and one Mn(3) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Mn(2), and two equivalent Mn(3) atoms. In the sixth O site, O(6) is bonded to one Na(1), one Mn(3), and two equivalent Mn(2) atoms to form a mixture of corner and edge-sharing ONaMn3 trigonal pyramids.