K2Nb2O5 crystallizes in the orthorhombic Ima2 space group. K(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra and corners with two equivalent Nb(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 2°. In the second Nb site, Nb(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form NbO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Nb(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent K(1) and two equivalent Nb(1) atoms to form distorted OK4Nb2 octahedra that share corners with two equivalent O(1)K4Nb2 octahedra, corners with four equivalent O(3)K2Nb2 tetrahedra, edges with two equivalent O(1)K4Nb2 octahedra, and faces with four equivalent O(1)K4Nb2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent K(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded to two equivalent K(1) and two equivalent Nb(2) atoms to form distorted OK2Nb2 tetrahedra that share corners with eight equivalent O(1)K4Nb2 octahedra and corners with two equivalent O(3)K2Nb2 tetrahedra. The corner-sharing octahedral tilt angles range from 17-82°.
K2Nb2O5 crystallizes in the orthorhombic Ima2 space group. K(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. The K(1)-O(3) bond length is 2.59 Å. There are a spread of K(1)-O(1) bond distances ranging from 2.69-2.80 Å. There are a spread of K(1)-O(2) bond distances ranging from 2.79-3.09 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra and corners with two equivalent Nb(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 2°. Both Nb(1)-O(2) bond lengths are 2.12 Å. There are two shorter (2.05 Å) and two longer (2.09 Å) Nb(1)-O(1) bond lengths. In the second Nb site, Nb(2) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form NbO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Nb(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. Both Nb(2)-O(2) bond lengths are 1.96 Å. Both Nb(2)-O(3) bond lengths are 1.95 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent K(1) and two equivalent Nb(1) atoms to form distorted OK4Nb2 octahedra that share corners with two equivalent O(1)K4Nb2 octahedra, corners with four equivalent O(3)K2Nb2 tetrahedra, edges with two equivalent O(1)K4Nb2 octahedra, and faces with four equivalent O(1)K4Nb2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent K(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded to two equivalent K(1) and two equivalent Nb(2) atoms to form distorted OK2Nb2 tetrahedra that share corners with eight equivalent O(1)K4Nb2 octahedra and corners with two equivalent O(3)K2Nb2 tetrahedra. The corner-sharing octahedral tilt angles range from 17-82°.