Na2VP2O8 crystallizes in the tetragonal P4bm space group. Na(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(4), and four equivalent O(2) atoms. V(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(2) atoms. P(1) is bonded to one O(1), one O(4), and two equivalent O(2) atoms to form corner-sharing PO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Na(1) and two equivalent P(1) atoms. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Na(1), one V(1), and one P(1) atom. In the third O site, O(3) is bonded in a single-bond geometry to one V(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to three equivalent Na(1) and one P(1) atom.
Na2VP2O8 crystallizes in the tetragonal P4bm space group. Na(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(4), and four equivalent O(2) atoms. The Na(1)-O(1) bond length is 2.70 Å. There is one shorter (2.59 Å) and two longer (2.84 Å) Na(1)-O(4) bond lengths. There are two shorter (2.66 Å) and two longer (2.83 Å) Na(1)-O(2) bond lengths. V(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(2) atoms. The V(1)-O(3) bond length is 1.63 Å. All V(1)-O(2) bond lengths are 1.99 Å. P(1) is bonded to one O(1), one O(4), and two equivalent O(2) atoms to form corner-sharing PO4 tetrahedra. The P(1)-O(1) bond length is 1.64 Å. The P(1)-O(4) bond length is 1.50 Å. Both P(1)-O(2) bond lengths are 1.54 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Na(1) and two equivalent P(1) atoms. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Na(1), one V(1), and one P(1) atom. In the third O site, O(3) is bonded in a single-bond geometry to one V(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to three equivalent Na(1) and one P(1) atom.