CsTiNb(O2F)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to one O(4), two equivalent O(1), two equivalent O(2), and one F(1) atom to form distorted CsO5F octahedra that share corners with six equivalent Ti(1)O3F3 octahedra and corners with six equivalent Nb(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 67-70°. In the second Cs site, Cs(2) is bonded to one O(3), two equivalent O(5), one F(3), and two equivalent F(2) atoms to form distorted CsO3F3 octahedra that share corners with six equivalent Ti(1)O3F3 octahedra and corners with six equivalent Nb(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 68-77°. Ti(1) is bonded to one O(1), one O(2), one O(5), one F(1), one F(2), and one F(3) atom to form TiO3F3 octahedra that share corners with two equivalent Ti(1)O3F3 octahedra, corners with three equivalent Cs(2)O3F3 octahedra, corners with three equivalent Cs(1)O5F octahedra, and corners with four equivalent Nb(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 28-76°. Nb(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one F(2) atom to form NbO5F octahedra that share corners with two equivalent Nb(1)O5F octahedra, corners with three equivalent Cs(2)O3F3 octahedra, corners with three equivalent Cs(1)O5F octahedra, and corners with four equivalent Ti(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 28-77°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Cs(1), one Ti(1), and one Nb(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Cs(1), one Ti(1), and one Nb(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cs(2) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Cs(1) and two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Cs(2), one Ti(1), and one Nb(1) atom. There are three inequivalent F sites. In the first F site, F(1) is bonded in a 2-coordinate geometry to one Cs(1) and two equivalent Ti(1) atoms. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Cs(2), one Ti(1), and one Nb(1) atom. In the third F site, F(3) is bonded in a distorted bent 150 degrees geometry to one Cs(2) and two equivalent Ti(1) atoms.
CsTiNb(O2F)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to one O(4), two equivalent O(1), two equivalent O(2), and one F(1) atom to form distorted CsO5F octahedra that share corners with six equivalent Ti(1)O3F3 octahedra and corners with six equivalent Nb(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 67-70°. The Cs(1)-O(4) bond length is 3.21 Å. Both Cs(1)-O(1) bond lengths are 3.20 Å. Both Cs(1)-O(2) bond lengths are 3.48 Å. The Cs(1)-F(1) bond length is 3.28 Å. In the second Cs site, Cs(2) is bonded to one O(3), two equivalent O(5), one F(3), and two equivalent F(2) atoms to form distorted CsO3F3 octahedra that share corners with six equivalent Ti(1)O3F3 octahedra and corners with six equivalent Nb(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 68-77°. The Cs(2)-O(3) bond length is 3.24 Å. Both Cs(2)-O(5) bond lengths are 3.53 Å. The Cs(2)-F(3) bond length is 3.27 Å. Both Cs(2)-F(2) bond lengths are 3.16 Å. Ti(1) is bonded to one O(1), one O(2), one O(5), one F(1), one F(2), and one F(3) atom to form TiO3F3 octahedra that share corners with two equivalent Ti(1)O3F3 octahedra, corners with three equivalent Cs(2)O3F3 octahedra, corners with three equivalent Cs(1)O5F octahedra, and corners with four equivalent Nb(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 28-76°. The Ti(1)-O(1) bond length is 1.85 Å. The Ti(1)-O(2) bond length is 1.89 Å. The Ti(1)-O(5) bond length is 1.88 Å. The Ti(1)-F(1) bond length is 2.03 Å. The Ti(1)-F(2) bond length is 2.09 Å. The Ti(1)-F(3) bond length is 2.01 Å. Nb(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one F(2) atom to form NbO5F octahedra that share corners with two equivalent Nb(1)O5F octahedra, corners with three equivalent Cs(2)O3F3 octahedra, corners with three equivalent Cs(1)O5F octahedra, and corners with four equivalent Ti(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 28-77°. The Nb(1)-O(1) bond length is 1.94 Å. The Nb(1)-O(2) bond length is 1.99 Å. The Nb(1)-O(3) bond length is 1.98 Å. The Nb(1)-O(4) bond length is 2.00 Å. The Nb(1)-O(5) bond length is 1.98 Å. The Nb(1)-F(2) bond length is 2.20 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Cs(1), one Ti(1), and one Nb(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Cs(1), one Ti(1), and one Nb(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cs(2) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Cs(1) and two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Cs(2), one Ti(1), and one Nb(1) atom. There are three inequivalent F sites. In the first F site, F(1) is bonded in a 2-coordinate geometry to one Cs(1) and two equivalent Ti(1) atoms. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Cs(2), one Ti(1), and one Nb(1) atom. In the third F site, F(3) is bonded in a distorted bent 150 degrees geometry to one Cs(2) and two equivalent Ti(1) atoms.