Na3Mn8O16 is beta indium sulfide-derived structured and crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2) and two equivalent O(5) atoms to form NaO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, and corners with four equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-67°. In the second Na site, Na(2) is bonded to one O(6), one O(7), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and corners with four equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-63°. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. In the second Mn site, Mn(2) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share  a cornercorner with one Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra,  an edgeedge with one Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. In the third Mn site, Mn(3) is bonded to one O(1), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra,  an edgeedge with one Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. In the fourth Mn site, Mn(4) is bonded to one O(4), one O(5), two equivalent O(6), and two equivalent O(7) atoms to form MnO6 octahedra that share  a cornercorner with one Na(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. There are seven inequivalent O sites. In the first O site, O(5) is bonded to one Na(1), one Mn(4), and two equivalent Mn(3) atoms to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the second O site, O(6) is bonded to one Na(2), one Mn(2), and two equivalent Mn(4) atoms to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the third O site, O(7) is bonded to one Na(2), one Mn(3), and two equivalent Mn(4) atoms to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the fourth O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Mn(3) and two equivalent Mn(1) atoms. In the fifth O site, O(2) is bonded to one Na(1), one Mn(2), and two equivalent Mn(1) atoms to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the sixth O site, O(3) is bonded to one Na(2), one Mn(1), one Mn(2), and one Mn(3) atom to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the seventh O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Mn(4) and two equivalent Mn(2) atoms.
Na3Mn8O16 is beta indium sulfide-derived structured and crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2) and two equivalent O(5) atoms to form NaO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, and corners with four equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-67°. Both Na(1)-O(2) bond lengths are 2.15 Å. Both Na(1)-O(5) bond lengths are 2.16 Å. In the second Na site, Na(2) is bonded to one O(6), one O(7), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and corners with four equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 60-63°. The Na(2)-O(6) bond length is 2.19 Å. The Na(2)-O(7) bond length is 2.16 Å. Both Na(2)-O(3) bond lengths are 2.17 Å. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(3)O6 octahedra. Both Mn(1)-O(1) bond lengths are 2.03 Å. Both Mn(1)-O(2) bond lengths are 2.00 Å. Both Mn(1)-O(3) bond lengths are 1.95 Å. In the second Mn site, Mn(2) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share  a cornercorner with one Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra,  an edgeedge with one Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. The Mn(2)-O(2) bond length is 1.99 Å. The Mn(2)-O(6) bond length is 1.93 Å. Both Mn(2)-O(3) bond lengths are 2.01 Å. Both Mn(2)-O(4) bond lengths are 2.01 Å. In the third Mn site, Mn(3) is bonded to one O(1), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra,  an edgeedge with one Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. The Mn(3)-O(1) bond length is 1.96 Å. The Mn(3)-O(7) bond length is 1.96 Å. Both Mn(3)-O(3) bond lengths are 2.05 Å. Both Mn(3)-O(5) bond lengths are 2.05 Å. In the fourth Mn site, Mn(4) is bonded to one O(4), one O(5), two equivalent O(6), and two equivalent O(7) atoms to form MnO6 octahedra that share  a cornercorner with one Na(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. The Mn(4)-O(4) bond length is 1.99 Å. The Mn(4)-O(5) bond length is 1.95 Å. Both Mn(4)-O(6) bond lengths are 2.04 Å. Both Mn(4)-O(7) bond lengths are 2.03 Å. There are seven inequivalent O sites. In the first O site, O(5) is bonded to one Na(1), one Mn(4), and two equivalent Mn(3) atoms to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the second O site, O(6) is bonded to one Na(2), one Mn(2), and two equivalent Mn(4) atoms to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the third O site, O(7) is bonded to one Na(2), one Mn(3), and two equivalent Mn(4) atoms to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the fourth O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Mn(3) and two equivalent Mn(1) atoms. In the fifth O site, O(2) is bonded to one Na(1), one Mn(2), and two equivalent Mn(1) atoms to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the sixth O site, O(3) is bonded to one Na(2), one Mn(1), one Mn(2), and one Mn(3) atom to form a mixture of edge and corner-sharing ONaMn3 tetrahedra. In the seventh O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Mn(4) and two equivalent Mn(2) atoms.