Na2V2O5 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), one O(9), and two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), one O(8), and two equivalent O(6) atoms. In the third Na site, Na(3) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), one O(5), and two equivalent O(7) atoms. In the fourth Na site, Na(4) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(9), and two equivalent O(8) atoms. There are four inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form VO6 octahedra that share corners with four equivalent V(2)O6 octahedra,  a cornercorner with one V(3)O4 tetrahedra, and  a cornercorner with one V(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-10°. In the second V site, V(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form VO6 octahedra that share corners with four equivalent V(1)O6 octahedra,  a cornercorner with one V(3)O4 tetrahedra, and  a cornercorner with one V(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-10°. In the third V site, V(3) is bonded to one O(10), one O(5), one O(8), and one O(9) atom to form VO4 tetrahedra that share  a cornercorner with one V(1)O6 octahedra,  a cornercorner with one V(2)O6 octahedra, and corners with two equivalent V(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-37°. In the fourth V site, V(4) is bonded to one O(10), one O(6), one O(7), and one O(9) atom to form VO4 tetrahedra that share  a cornercorner with one V(1)O6 octahedra,  a cornercorner with one V(2)O6 octahedra, and corners with two equivalent V(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-37°. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one V(1), and one V(2) atom to form distorted ONa4V2 octahedra that share corners with two equivalent O(4)Na4V2 octahedra, corners with two equivalent O(10)Na2V2 tetrahedra, corners with two equivalent O(9)Na2V2 tetrahedra, edges with two equivalent O(4)Na4V2 octahedra, faces with two equivalent O(2)Na4V2 octahedra, and faces with two equivalent O(3)Na4V2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one V(1), and one V(2) atom to form distorted ONa4V2 octahedra that share corners with two equivalent O(3)Na4V2 octahedra, corners with two equivalent O(10)Na2V2 tetrahedra, corners with two equivalent O(9)Na2V2 tetrahedra, edges with two equivalent O(3)Na4V2 octahedra, faces with two equivalent O(1)Na4V2 octahedra, and faces with two equivalent O(4)Na4V2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one V(1), and one V(2) atom to form distorted ONa4V2 octahedra that share corners with two equivalent O(2)Na4V2 octahedra, corners with two equivalent O(10)Na2V2 tetrahedra, corners with two equivalent O(9)Na2V2 tetrahedra, edges with two equivalent O(2)Na4V2 octahedra, faces with two equivalent O(1)Na4V2 octahedra, and faces with two equivalent O(4)Na4V2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one V(1), and one V(2) atom to form distorted ONa4V2 octahedra that share corners with two equivalent O(1)Na4V2 octahedra, corners with two equivalent O(10)Na2V2 tetrahedra, corners with two equivalent O(9)Na2V2 tetrahedra, edges with two equivalent O(1)Na4V2 octahedra, faces with two equivalent O(2)Na4V2 octahedra, and faces with two equivalent O(3)Na4V2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(3), two equivalent Na(1), one V(1), and one V(3) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(4), two equivalent Na(2), one V(1), and one V(4) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(3), one V(2), and one V(4) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(4), one V(2), and one V(3) atom. In the ninth O site, O(9) is bonded to one Na(1), one Na(4), one V(3), and one V(4) atom to form distorted ONa2V2 tetrahedra that share corners with two equivalent O(1)Na4V2 octahedra, corners with two equivalent O(2)Na4V2 octahedra, corners with two equivalent O(3)Na4V2 octahedra, corners with two equivalent O(4)Na4V2 octahedra, and corners with two equivalent O(10)Na2V2 tetrahedra. The corner-sharing octahedral tilt angles range from 19-84°. In the tenth O site, O(10) is bonded to one Na(2), one Na(3), one V(3), and one V(4) atom to form distorted ONa2V2 tetrahedra that share corners with two equivalent O(1)Na4V2 octahedra, corners with two equivalent O(2)Na4V2 octahedra, corners with two equivalent O(3)Na4V2 octahedra, corners with two equivalent O(4)Na4V2 octahedra, and corners with two equivalent O(9)Na2V2 tetrahedra. The corner-sharing octahedral tilt angles range from 19-84°.
Na2V2O5 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), one O(9), and two equivalent O(5) atoms. The Na(1)-O(1) bond length is 2.48 Å. The Na(1)-O(2) bond length is 2.48 Å. The Na(1)-O(3) bond length is 2.57 Å. The Na(1)-O(4) bond length is 2.52 Å. The Na(1)-O(7) bond length is 2.36 Å. The Na(1)-O(9) bond length is 2.33 Å. There is one shorter (2.62 Å) and one longer (2.90 Å) Na(1)-O(5) bond length. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), one O(8), and two equivalent O(6) atoms. The Na(2)-O(1) bond length is 2.44 Å. The Na(2)-O(10) bond length is 2.33 Å. The Na(2)-O(2) bond length is 2.50 Å. The Na(2)-O(3) bond length is 2.55 Å. The Na(2)-O(4) bond length is 2.55 Å. The Na(2)-O(8) bond length is 2.35 Å. There is one shorter (2.62 Å) and one longer (2.89 Å) Na(2)-O(6) bond length. In the third Na site, Na(3) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), one O(5), and two equivalent O(7) atoms. The Na(3)-O(1) bond length is 2.57 Å. The Na(3)-O(10) bond length is 2.34 Å. The Na(3)-O(2) bond length is 2.51 Å. The Na(3)-O(3) bond length is 2.48 Å. The Na(3)-O(4) bond length is 2.48 Å. The Na(3)-O(5) bond length is 2.35 Å. There is one shorter (2.61 Å) and one longer (2.90 Å) Na(3)-O(7) bond length. In the fourth Na site, Na(4) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), one O(9), and two equivalent O(8) atoms. The Na(4)-O(1) bond length is 2.55 Å. The Na(4)-O(2) bond length is 2.55 Å. The Na(4)-O(3) bond length is 2.44 Å. The Na(4)-O(4) bond length is 2.49 Å. The Na(4)-O(6) bond length is 2.35 Å. The Na(4)-O(9) bond length is 2.34 Å. There is one shorter (2.62 Å) and one longer (2.89 Å) Na(4)-O(8) bond length. There are four inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form VO6 octahedra that share corners with four equivalent V(2)O6 octahedra,  a cornercorner with one V(3)O4 tetrahedra, and  a cornercorner with one V(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-10°. The V(1)-O(1) bond length is 1.85 Å. The V(1)-O(2) bond length is 2.08 Å. The V(1)-O(3) bond length is 2.04 Å. The V(1)-O(4) bond length is 1.83 Å. The V(1)-O(5) bond length is 2.09 Å. The V(1)-O(6) bond length is 2.09 Å. In the second V site, V(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form VO6 octahedra that share corners with four equivalent V(1)O6 octahedra,  a cornercorner with one V(3)O4 tetrahedra, and  a cornercorner with one V(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-10°. The V(2)-O(1) bond length is 2.04 Å. The V(2)-O(2) bond length is 1.83 Å. The V(2)-O(3) bond length is 1.85 Å. The V(2)-O(4) bond length is 2.08 Å. The V(2)-O(7) bond length is 2.08 Å. The V(2)-O(8) bond length is 2.09 Å. In the third V site, V(3) is bonded to one O(10), one O(5), one O(8), and one O(9) atom to form VO4 tetrahedra that share  a cornercorner with one V(1)O6 octahedra,  a cornercorner with one V(2)O6 octahedra, and corners with two equivalent V(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-37°. The V(3)-O(10) bond length is 1.88 Å. The V(3)-O(5) bond length is 1.77 Å. The V(3)-O(8) bond length is 1.77 Å. The V(3)-O(9) bond length is 1.89 Å. In the fourth V site, V(4) is bonded to one O(10), one O(6), one O(7), and one O(9) atom to form VO4 tetrahedra that share  a cornercorner with one V(1)O6 octahedra,  a cornercorner with one V(2)O6 octahedra, and corners with two equivalent V(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-37°. The V(4)-O(10) bond length is 1.89 Å. The V(4)-O(6) bond length is 1.77 Å. The V(4)-O(7) bond length is 1.77 Å. The V(4)-O(9) bond length is 1.88 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one V(1), and one V(2) atom to form distorted ONa4V2 octahedra that share corners with two equivalent O(4)Na4V2 octahedra, corners with two equivalent O(10)Na2V2 tetrahedra, corners with two equivalent O(9)Na2V2 tetrahedra, edges with two equivalent O(4)Na4V2 octahedra, faces with two equivalent O(2)Na4V2 octahedra, and faces with two equivalent O(3)Na4V2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one V(1), and one V(2) atom to form distorted ONa4V2 octahedra that share corners with two equivalent O(3)Na4V2 octahedra, corners with two equivalent O(10)Na2V2 tetrahedra, corners with two equivalent O(9)Na2V2 tetrahedra, edges with two equivalent O(3)Na4V2 octahedra, faces with two equivalent O(1)Na4V2 octahedra, and faces with two equivalent O(4)Na4V2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one V(1), and one V(2) atom to form distorted ONa4V2 octahedra that share corners with two equivalent O(2)Na4V2 octahedra, corners with two equivalent O(10)Na2V2 tetrahedra, corners with two equivalent O(9)Na2V2 tetrahedra, edges with two equivalent O(2)Na4V2 octahedra, faces with two equivalent O(1)Na4V2 octahedra, and faces with two equivalent O(4)Na4V2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one V(1), and one V(2) atom to form distorted ONa4V2 octahedra that share corners with two equivalent O(1)Na4V2 octahedra, corners with two equivalent O(10)Na2V2 tetrahedra, corners with two equivalent O(9)Na2V2 tetrahedra, edges with two equivalent O(1)Na4V2 octahedra, faces with two equivalent O(2)Na4V2 octahedra, and faces with two equivalent O(3)Na4V2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(3), two equivalent Na(1), one V(1), and one V(3) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(4), two equivalent Na(2), one V(1), and one V(4) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(3), one V(2), and one V(4) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(2), two equivalent Na(4), one V(2), and one V(3) atom. In the ninth O site, O(9) is bonded to one Na(1), one Na(4), one V(3), and one V(4) atom to form distorted ONa2V2 tetrahedra that share corners with two equivalent O(1)Na4V2 octahedra, corners with two equivalent O(2)Na4V2 octahedra, corners with two equivalent O(3)Na4V2 octahedra, corners with two equivalent O(4)Na4V2 octahedra, and corners with two equivalent O(10)Na2V2 tetrahedra. The corner-sharing octahedral tilt angles range from 19-84°. In the tenth O site, O(10) is bonded to one Na(2), one Na(3), one V(3), and one V(4) atom to form distorted ONa2V2 tetrahedra that share corners with two equivalent O(1)Na4V2 octahedra, corners with two equivalent O(2)Na4V2 octahedra, corners with two equivalent O(3)Na4V2 octahedra, corners with two equivalent O(4)Na4V2 octahedra, and corners with two equivalent O(9)Na2V2 tetrahedra. The corner-sharing octahedral tilt angles range from 19-84°.