K2NbO3F is (La,Ba)CuO4-derived structured and crystallizes in the tetragonal I4mm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to one O(2), four equivalent O(1), and four equivalent F(1) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to four equivalent O(1), four equivalent O(2), and one F(1) atom. Nb(1) is bonded to one O(2), four equivalent O(1), and one F(1) atom to form corner-sharing NbO5F octahedra. The corner-sharing octahedral tilt angles are 13°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to two equivalent K(1), two equivalent K(2), and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded to one K(1), four equivalent K(2), and one Nb(1) atom to form distorted OK5Nb octahedra that share  a cornercorner with one F(1)K5Nb octahedra, corners with four equivalent O(2)K5Nb octahedra, edges with four equivalent O(2)K5Nb octahedra, and edges with four equivalent F(1)K5Nb octahedra. The corner-sharing octahedral tilt angles range from 0-6°. F(1) is bonded to one K(2), four equivalent K(1), and one Nb(1) atom to form FK5Nb octahedra that share  a cornercorner with one O(2)K5Nb octahedra, corners with four equivalent F(1)K5Nb octahedra, edges with four equivalent O(2)K5Nb octahedra, and edges with four equivalent F(1)K5Nb octahedra. The corner-sharing octahedral tilt angles range from 0-2°.
K2NbO3F is (La,Ba)CuO4-derived structured and crystallizes in the tetragonal I4mm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to one O(2), four equivalent O(1), and four equivalent F(1) atoms. The K(1)-O(2) bond length is 2.85 Å. All K(1)-O(1) bond lengths are 2.86 Å. All K(1)-F(1) bond lengths are 2.84 Å. In the second K site, K(2) is bonded in a 9-coordinate geometry to four equivalent O(1), four equivalent O(2), and one F(1) atom. All K(2)-O(1) bond lengths are 2.99 Å. All K(2)-O(2) bond lengths are 2.84 Å. The K(2)-F(1) bond length is 2.65 Å. Nb(1) is bonded to one O(2), four equivalent O(1), and one F(1) atom to form corner-sharing NbO5F octahedra. The corner-sharing octahedral tilt angles are 13°. The Nb(1)-O(2) bond length is 1.84 Å. All Nb(1)-O(1) bond lengths are 2.02 Å. The Nb(1)-F(1) bond length is 2.33 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to two equivalent K(1), two equivalent K(2), and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded to one K(1), four equivalent K(2), and one Nb(1) atom to form distorted OK5Nb octahedra that share  a cornercorner with one F(1)K5Nb octahedra, corners with four equivalent O(2)K5Nb octahedra, edges with four equivalent O(2)K5Nb octahedra, and edges with four equivalent F(1)K5Nb octahedra. The corner-sharing octahedral tilt angles range from 0-6°. F(1) is bonded to one K(2), four equivalent K(1), and one Nb(1) atom to form FK5Nb octahedra that share  a cornercorner with one O(2)K5Nb octahedra, corners with four equivalent F(1)K5Nb octahedra, edges with four equivalent O(2)K5Nb octahedra, and edges with four equivalent F(1)K5Nb octahedra. The corner-sharing octahedral tilt angles range from 0-2°.