Na8MgV2O8 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(3), one O(4), and one O(7) atom. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(7) atom. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(5), and one O(6) atom. In the fourth Na site, Na(4) 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 fifth Na site, Na(5) is bonded in a distorted trigonal non-coplanar geometry to one O(4), one O(5), and one O(8) atom. In the sixth Na site, Na(6) is bonded in a 4-coordinate 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 4-coordinate geometry to one O(5), one O(6), one O(7), and one O(8) atom. In the eighth Na site, Na(8) is bonded in a 4-coordinate geometry to one O(1), one O(6), one O(7), and one O(8) atom. Mg(1) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form MgO4 tetrahedra that share  a cornercorner with one V(1)O4 tetrahedra and corners with three equivalent V(2)O4 tetrahedra. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form VO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra. In the second V site, V(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form VO4 tetrahedra that share corners with three equivalent Mg(1)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(8), one Mg(1), and one V(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Mg(1), and one V(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), and one V(1) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one V(1) atom to form corner-sharing ONa5V octahedra. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), one Na(7), and one V(1) atom. In the sixth O site, O(6) is bonded to one Na(3), one Na(6), one Na(7), one Na(8), and one V(1) atom to form corner-sharing ONa4V trigonal bipyramids. The corner-sharing octahedral tilt angles range from 43-65°. In the seventh O site, O(7) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(6), one Na(7), one Na(8), one Mg(1), and one V(2) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(5), one Na(6), one Na(7), one Na(8), and one V(2) atom.
Na8MgV2O8 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(3), one O(4), and one O(7) atom. The Na(1)-O(1) bond length is 2.27 Å. The Na(1)-O(2) bond length is 2.59 Å. The Na(1)-O(3) bond length is 2.30 Å. The Na(1)-O(4) bond length is 2.24 Å. The Na(1)-O(7) bond length is 2.93 Å. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(7) atom. The Na(2)-O(1) bond length is 2.94 Å. The Na(2)-O(2) bond length is 2.32 Å. The Na(2)-O(3) bond length is 2.54 Å. The Na(2)-O(4) bond length is 2.30 Å. The Na(2)-O(7) bond length is 2.44 Å. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(5), and one O(6) atom. The Na(3)-O(3) bond length is 2.39 Å. The Na(3)-O(4) bond length is 2.32 Å. The Na(3)-O(5) bond length is 2.37 Å. The Na(3)-O(6) bond length is 2.38 Å. In the fourth Na site, Na(4) 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(4)-O(1) bond length is 2.71 Å. The Na(4)-O(2) bond length is 2.40 Å. The Na(4)-O(3) bond length is 2.96 Å. The Na(4)-O(4) bond length is 2.38 Å. The Na(4)-O(5) bond length is 2.48 Å. In the fifth Na site, Na(5) is bonded in a distorted trigonal non-coplanar geometry to one O(4), one O(5), and one O(8) atom. The Na(5)-O(4) bond length is 2.30 Å. The Na(5)-O(5) bond length is 2.37 Å. The Na(5)-O(8) bond length is 2.28 Å. In the sixth Na site, Na(6) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(7), and one O(8) atom. The Na(6)-O(5) bond length is 2.48 Å. The Na(6)-O(6) bond length is 2.23 Å. The Na(6)-O(7) bond length is 2.36 Å. The Na(6)-O(8) bond length is 2.41 Å. In the seventh Na site, Na(7) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(7), and one O(8) atom. The Na(7)-O(5) bond length is 2.40 Å. The Na(7)-O(6) bond length is 2.38 Å. The Na(7)-O(7) bond length is 2.66 Å. The Na(7)-O(8) bond length is 2.41 Å. In the eighth Na site, Na(8) is bonded in a 4-coordinate geometry to one O(1), one O(6), one O(7), and one O(8) atom. The Na(8)-O(1) bond length is 2.51 Å. The Na(8)-O(6) bond length is 2.25 Å. The Na(8)-O(7) bond length is 2.59 Å. The Na(8)-O(8) bond length is 2.42 Å. Mg(1) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form MgO4 tetrahedra that share  a cornercorner with one V(1)O4 tetrahedra and corners with three equivalent V(2)O4 tetrahedra. The Mg(1)-O(1) bond length is 1.97 Å. The Mg(1)-O(2) bond length is 1.96 Å. The Mg(1)-O(3) bond length is 2.00 Å. The Mg(1)-O(7) bond length is 2.03 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form VO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra. The V(1)-O(3) bond length is 1.97 Å. The V(1)-O(4) bond length is 1.95 Å. The V(1)-O(5) bond length is 1.94 Å. The V(1)-O(6) bond length is 1.92 Å. In the second V site, V(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form VO4 tetrahedra that share corners with three equivalent Mg(1)O4 tetrahedra. The V(2)-O(1) bond length is 1.98 Å. The V(2)-O(2) bond length is 1.96 Å. The V(2)-O(7) bond length is 2.00 Å. The V(2)-O(8) bond length is 1.88 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(8), one Mg(1), and one V(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Mg(1), and one V(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Mg(1), and one V(1) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one V(1) atom to form corner-sharing ONa5V octahedra. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), one Na(7), and one V(1) atom. In the sixth O site, O(6) is bonded to one Na(3), one Na(6), one Na(7), one Na(8), and one V(1) atom to form corner-sharing ONa4V trigonal bipyramids. The corner-sharing octahedral tilt angles range from 43-65°. In the seventh O site, O(7) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(6), one Na(7), one Na(8), one Mg(1), and one V(2) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(5), one Na(6), one Na(7), one Na(8), and one V(2) atom.