K5(NbO3)4F is Pb (Zr_0.50 Ti_0.48) O_3-derived structured and crystallizes in the monoclinic P2_1/c space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one F(1) atom. In the second K site, K(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent F(1) atoms to form corner-sharing KO4F2 octahedra. The corner-sharing octahedra are not tilted. In the third K site, K(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and one F(1) atom. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(5), and two equivalent O(6) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and two equivalent O(6) atoms. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to one K(1), one K(3), one Nb(1), and one Nb(2) atom. In the second O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Nb(1) and two equivalent Nb(2) atoms. In the third O site, O(1) is bonded to one K(1), one K(3), one Nb(1), and one Nb(2) atom to form distorted OK2Nb2 tetrahedra that share corners with two equivalent F(1)K6 octahedra. The corner-sharing octahedral tilt angles range from 45-60°. In the fourth O site, O(2) is bonded in a 1-coordinate geometry to one K(1), one K(2), one K(3), and one Nb(1) atom. In the fifth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one K(2), one K(3), and one Nb(2) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Nb(1), and one Nb(2) atom. F(1) is bonded to two equivalent K(1), two equivalent K(2), and two equivalent K(3) atoms to form FK6 octahedra that share corners with two equivalent F(1)K6 octahedra and corners with four equivalent O(1)K2Nb2 tetrahedra. The corner-sharing octahedra are not tilted.
K5(NbO3)4F is Pb (Zr_0.50 Ti_0.48) O_3-derived structured and crystallizes in the monoclinic P2_1/c space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one F(1) atom. The K(1)-O(1) bond length is 2.84 Å. The K(1)-O(2) bond length is 2.93 Å. The K(1)-O(3) bond length is 2.70 Å. The K(1)-O(4) bond length is 2.63 Å. The K(1)-O(5) bond length is 3.03 Å. The K(1)-F(1) bond length is 2.69 Å. In the second K site, K(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent F(1) atoms to form corner-sharing KO4F2 octahedra. The corner-sharing octahedra are not tilted. Both K(2)-O(2) bond lengths are 2.67 Å. Both K(2)-O(3) bond lengths are 2.61 Å. Both K(2)-F(1) bond lengths are 2.57 Å. In the third K site, K(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and one F(1) atom. The K(3)-O(1) bond length is 2.82 Å. The K(3)-O(2) bond length is 2.77 Å. The K(3)-O(3) bond length is 2.79 Å. The K(3)-O(5) bond length is 2.66 Å. The K(3)-F(1) bond length is 2.69 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(5), and two equivalent O(6) atoms. The Nb(1)-O(1) bond length is 2.01 Å. The Nb(1)-O(2) bond length is 1.80 Å. The Nb(1)-O(4) bond length is 1.93 Å. The Nb(1)-O(5) bond length is 2.07 Å. There is one shorter (2.08 Å) and one longer (2.46 Å) Nb(1)-O(6) bond length. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and two equivalent O(6) atoms. The Nb(2)-O(1) bond length is 1.99 Å. The Nb(2)-O(3) bond length is 1.80 Å. The Nb(2)-O(4) bond length is 2.08 Å. The Nb(2)-O(5) bond length is 1.94 Å. There is one shorter (2.08 Å) and one longer (2.44 Å) Nb(2)-O(6) bond length. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to one K(1), one K(3), one Nb(1), and one Nb(2) atom. In the second O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Nb(1) and two equivalent Nb(2) atoms. In the third O site, O(1) is bonded to one K(1), one K(3), one Nb(1), and one Nb(2) atom to form distorted OK2Nb2 tetrahedra that share corners with two equivalent F(1)K6 octahedra. The corner-sharing octahedral tilt angles range from 45-60°. In the fourth O site, O(2) is bonded in a 1-coordinate geometry to one K(1), one K(2), one K(3), and one Nb(1) atom. In the fifth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one K(2), one K(3), and one Nb(2) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Nb(1), and one Nb(2) atom. F(1) is bonded to two equivalent K(1), two equivalent K(2), and two equivalent K(3) atoms to form FK6 octahedra that share corners with two equivalent F(1)K6 octahedra and corners with four equivalent O(1)K2Nb2 tetrahedra. The corner-sharing octahedra are not tilted.