Na6V2O7 crystallizes in the monoclinic Pc space group. There are six inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(2), one O(5), one O(6), and one O(7) atom. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to one O(4), one O(5), one O(6), and one O(7) atom. In the third Na site, Na(3) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one V(1)O4 tetrahedra, corners with two equivalent V(2)O4 tetrahedra, and  an edgeedge with one V(1)O4 tetrahedra. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(6), and one O(7) atom. In the fifth Na site, Na(5) is bonded in a 4-coordinate geometry to one O(1), one O(4), one O(7), and two equivalent O(3) atoms. In the sixth Na site, Na(6) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form VO4 tetrahedra that share  a cornercorner with one V(2)O4 tetrahedra,  a cornercorner with one Na(3)O5 trigonal bipyramid, and  an edgeedge with one Na(3)O5 trigonal bipyramid. In the second V site, V(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form VO4 tetrahedra that share  a cornercorner with one V(1)O4 tetrahedra and corners with two equivalent Na(3)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), and one V(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(6), one V(1), and one V(2) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(6), two equivalent Na(5), and one V(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(2), one Na(5), one Na(6), and one V(2) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Na(3), and one V(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), and one V(1) atom. In the seventh O site, O(7) is bonded in a distorted octahedral geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one V(1) atom.
Na6V2O7 crystallizes in the monoclinic Pc space group. There are six inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(2), one O(5), one O(6), and one O(7) atom. The Na(1)-O(2) bond length is 2.50 Å. The Na(1)-O(5) bond length is 2.24 Å. The Na(1)-O(6) bond length is 2.42 Å. The Na(1)-O(7) bond length is 2.61 Å. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to one O(4), one O(5), one O(6), and one O(7) atom. The Na(2)-O(4) bond length is 2.70 Å. The Na(2)-O(5) bond length is 2.34 Å. The Na(2)-O(6) bond length is 2.40 Å. The Na(2)-O(7) bond length is 2.53 Å. In the third Na site, Na(3) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one V(1)O4 tetrahedra, corners with two equivalent V(2)O4 tetrahedra, and  an edgeedge with one V(1)O4 tetrahedra. The Na(3)-O(1) bond length is 2.49 Å. The Na(3)-O(3) bond length is 2.32 Å. The Na(3)-O(5) bond length is 2.61 Å. The Na(3)-O(6) bond length is 2.48 Å. The Na(3)-O(7) bond length is 2.38 Å. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(6), and one O(7) atom. The Na(4)-O(1) bond length is 2.34 Å. The Na(4)-O(3) bond length is 2.34 Å. The Na(4)-O(6) bond length is 2.26 Å. The Na(4)-O(7) bond length is 2.40 Å. In the fifth Na site, Na(5) is bonded in a 4-coordinate geometry to one O(1), one O(4), one O(7), and two equivalent O(3) atoms. The Na(5)-O(1) bond length is 2.52 Å. The Na(5)-O(4) bond length is 2.43 Å. The Na(5)-O(7) bond length is 2.75 Å. There is one shorter (2.59 Å) and one longer (2.96 Å) Na(5)-O(3) bond length. In the sixth Na site, Na(6) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Na(6)-O(1) bond length is 2.39 Å. The Na(6)-O(2) bond length is 2.41 Å. The Na(6)-O(3) bond length is 2.42 Å. The Na(6)-O(4) bond length is 2.25 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form VO4 tetrahedra that share  a cornercorner with one V(2)O4 tetrahedra,  a cornercorner with one Na(3)O5 trigonal bipyramid, and  an edgeedge with one Na(3)O5 trigonal bipyramid. The V(1)-O(2) bond length is 1.87 Å. The V(1)-O(5) bond length is 1.80 Å. The V(1)-O(6) bond length is 1.78 Å. The V(1)-O(7) bond length is 1.82 Å. In the second V site, V(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form VO4 tetrahedra that share  a cornercorner with one V(1)O4 tetrahedra and corners with two equivalent Na(3)O5 trigonal bipyramids. The V(2)-O(1) bond length is 1.78 Å. The V(2)-O(2) bond length is 1.90 Å. The V(2)-O(3) bond length is 1.84 Å. The V(2)-O(4) bond length is 1.78 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), and one V(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(6), one V(1), and one V(2) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(6), two equivalent Na(5), and one V(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(2), one Na(5), one Na(6), and one V(2) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Na(3), and one V(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), and one V(1) atom. In the seventh O site, O(7) is bonded in a distorted octahedral geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one V(1) atom.