Na2W2O5 crystallizes in the orthorhombic Ima2 space group. Na(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(2), and four equivalent O(1) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form WO6 octahedra that share corners with four equivalent W(1)O6 octahedra and corners with two equivalent W(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 18°. In the second W site, W(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form WO4 tetrahedra that share corners with two equivalent W(1)O6 octahedra and corners with two equivalent W(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Na(1) and two equivalent W(1) atoms to form distorted ONa4W2 octahedra that share corners with two equivalent O(1)Na4W2 octahedra, corners with four equivalent O(3)Na2W2 tetrahedra, edges with two equivalent O(1)Na4W2 octahedra, and faces with four equivalent O(1)Na4W2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one W(1), and one W(2) atom. In the third O site, O(3) is bonded to two equivalent Na(1) and two equivalent W(2) atoms to form distorted ONa2W2 tetrahedra that share corners with eight equivalent O(1)Na4W2 octahedra and corners with two equivalent O(3)Na2W2 tetrahedra. The corner-sharing octahedral tilt angles range from 21-86°.
Na2W2O5 crystallizes in the orthorhombic Ima2 space group. Na(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(2), and four equivalent O(1) atoms. The Na(1)-O(3) bond length is 2.42 Å. There is one shorter (2.33 Å) and one longer (2.69 Å) Na(1)-O(2) bond length. There are a spread of Na(1)-O(1) bond distances ranging from 2.42-2.75 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form WO6 octahedra that share corners with four equivalent W(1)O6 octahedra and corners with two equivalent W(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 18°. Both W(1)-O(2) bond lengths are 2.16 Å. There are two shorter (2.06 Å) and two longer (2.07 Å) W(1)-O(1) bond lengths. In the second W site, W(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form WO4 tetrahedra that share corners with two equivalent W(1)O6 octahedra and corners with two equivalent W(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. Both W(2)-O(2) bond lengths are 1.94 Å. There is one shorter (2.00 Å) and one longer (2.04 Å) W(2)-O(3) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Na(1) and two equivalent W(1) atoms to form distorted ONa4W2 octahedra that share corners with two equivalent O(1)Na4W2 octahedra, corners with four equivalent O(3)Na2W2 tetrahedra, edges with two equivalent O(1)Na4W2 octahedra, and faces with four equivalent O(1)Na4W2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one W(1), and one W(2) atom. In the third O site, O(3) is bonded to two equivalent Na(1) and two equivalent W(2) atoms to form distorted ONa2W2 tetrahedra that share corners with eight equivalent O(1)Na4W2 octahedra and corners with two equivalent O(3)Na2W2 tetrahedra. The corner-sharing octahedral tilt angles range from 21-86°.