Na8MgMn2O8 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(7), and one O(8) atom. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), one O(7), and one O(8) atom. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(6) atom. In the fifth Na site, Na(5) is bonded in a 4-coordinate geometry to one O(4), one O(5), one O(6), one O(7), and one O(8) atom. In the sixth Na site, Na(6) is bonded in a distorted see-saw-like geometry to one O(5), one O(6), one O(7), and one O(8) atom. In the seventh Na site, Na(7) is bonded in a 5-coordinate geometry to one O(3), one O(5), one O(6), one O(7), and one O(8) atom. In the eighth Na site, Na(8) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form NaO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Mn(2)O4 tetrahedra, and  a cornercorner with one Mn(1)O4 trigonal pyramid. Mg(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form MgO4 tetrahedra that share  a cornercorner with one Na(8)O4 tetrahedra,  a cornercorner with one Mn(2)O4 tetrahedra, and corners with three equivalent Mn(1)O4 trigonal pyramids. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form distorted MnO4 trigonal pyramids that share  a cornercorner with one Na(8)O4 tetrahedra and corners with three equivalent Mg(1)O4 tetrahedra. In the second Mn site, Mn(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form distorted MnO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra and corners with three equivalent Na(8)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted octahedral geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(8), and one Mn(2) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(8), one Mg(1), and one Mn(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(7), one Mg(1), and one Mn(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(5), one Mg(1), and one Mn(1) atom. In the fifth O site, O(5) is bonded in a 7-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), one Na(7), one Mg(1), and one Mn(1) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(4), one Na(5), one Na(6), one Na(7), one Na(8), and one Mn(1) atom. In the seventh O site, O(7) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Na(7), one Na(8), and one Mn(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Na(7), and one Mn(2) atom.
Na8MgMn2O8 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(7), and one O(8) atom. The Na(1)-O(1) bond length is 2.25 Å. The Na(1)-O(2) bond length is 2.34 Å. The Na(1)-O(7) bond length is 2.27 Å. The Na(1)-O(8) bond length is 2.30 Å. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), one O(7), and one O(8) atom. The Na(2)-O(1) bond length is 2.44 Å. The Na(2)-O(2) bond length is 2.52 Å. The Na(2)-O(4) bond length is 2.93 Å. The Na(2)-O(7) bond length is 2.37 Å. The Na(2)-O(8) bond length is 2.37 Å. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The Na(3)-O(1) bond length is 2.30 Å. The Na(3)-O(2) bond length is 2.48 Å. The Na(3)-O(3) bond length is 2.58 Å. The Na(3)-O(4) bond length is 2.29 Å. The Na(3)-O(5) bond length is 2.60 Å. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(6) atom. The Na(4)-O(1) bond length is 2.36 Å. The Na(4)-O(3) bond length is 2.32 Å. The Na(4)-O(4) bond length is 2.68 Å. The Na(4)-O(5) bond length is 2.37 Å. The Na(4)-O(6) bond length is 2.55 Å. In the fifth Na site, Na(5) is bonded in a 4-coordinate geometry to one O(4), one O(5), one O(6), one O(7), and one O(8) atom. The Na(5)-O(4) bond length is 2.48 Å. The Na(5)-O(5) bond length is 2.41 Å. The Na(5)-O(6) bond length is 2.35 Å. The Na(5)-O(7) bond length is 2.85 Å. The Na(5)-O(8) bond length is 2.36 Å. In the sixth Na site, Na(6) is bonded in a distorted see-saw-like geometry to one O(5), one O(6), one O(7), and one O(8) atom. The Na(6)-O(5) bond length is 2.46 Å. The Na(6)-O(6) bond length is 2.38 Å. The Na(6)-O(7) bond length is 2.41 Å. The Na(6)-O(8) bond length is 2.58 Å. In the seventh Na site, Na(7) is bonded in a 5-coordinate geometry to one O(3), one O(5), one O(6), one O(7), and one O(8) atom. The Na(7)-O(3) bond length is 2.50 Å. The Na(7)-O(5) bond length is 2.67 Å. The Na(7)-O(6) bond length is 2.40 Å. The Na(7)-O(7) bond length is 2.73 Å. The Na(7)-O(8) bond length is 2.31 Å. In the eighth Na site, Na(8) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form NaO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Mn(2)O4 tetrahedra, and  a cornercorner with one Mn(1)O4 trigonal pyramid. The Na(8)-O(1) bond length is 2.34 Å. The Na(8)-O(2) bond length is 2.43 Å. The Na(8)-O(6) bond length is 2.51 Å. The Na(8)-O(7) bond length is 2.45 Å. Mg(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form MgO4 tetrahedra that share  a cornercorner with one Na(8)O4 tetrahedra,  a cornercorner with one Mn(2)O4 tetrahedra, and corners with three equivalent Mn(1)O4 trigonal pyramids. The Mg(1)-O(2) bond length is 2.01 Å. The Mg(1)-O(3) bond length is 1.96 Å. The Mg(1)-O(4) bond length is 1.97 Å. The Mg(1)-O(5) bond length is 2.00 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form distorted MnO4 trigonal pyramids that share  a cornercorner with one Na(8)O4 tetrahedra and corners with three equivalent Mg(1)O4 tetrahedra. The Mn(1)-O(3) bond length is 1.93 Å. The Mn(1)-O(4) bond length is 1.96 Å. The Mn(1)-O(5) bond length is 1.94 Å. The Mn(1)-O(6) bond length is 1.91 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form distorted MnO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra and corners with three equivalent Na(8)O4 tetrahedra. The Mn(2)-O(1) bond length is 1.91 Å. The Mn(2)-O(2) bond length is 2.00 Å. The Mn(2)-O(7) bond length is 1.92 Å. The Mn(2)-O(8) bond length is 1.93 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted octahedral geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(8), and one Mn(2) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(8), one Mg(1), and one Mn(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(7), one Mg(1), and one Mn(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(5), one Mg(1), and one Mn(1) atom. In the fifth O site, O(5) is bonded in a 7-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), one Na(7), one Mg(1), and one Mn(1) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(4), one Na(5), one Na(6), one Na(7), one Na(8), and one Mn(1) atom. In the seventh O site, O(7) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Na(7), one Na(8), and one Mn(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Na(7), and one Mn(2) atom.