CsTlF4 crystallizes in the orthorhombic Pca2_1 space group. Cs(1) is bonded in a 9-coordinate geometry to one F(2), two equivalent F(3), three equivalent F(1), and three equivalent F(4) atoms. Tl(1) is bonded to one F(1), one F(4), two equivalent F(2), and two equivalent F(3) atoms to form corner-sharing TlF6 octahedra. The corner-sharing octahedral tilt angles range from 32-42°. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted single-bond geometry to three equivalent Cs(1) and one Tl(1) atom. In the second F site, F(2) is bonded in a distorted bent 150 degrees geometry to one Cs(1) and two equivalent Tl(1) atoms. In the third F site, F(3) is bonded in a 4-coordinate geometry to two equivalent Cs(1) and two equivalent Tl(1) atoms. In the fourth F site, F(4) is bonded in a 4-coordinate geometry to three equivalent Cs(1) and one Tl(1) atom.
CsTlF4 crystallizes in the orthorhombic Pca2_1 space group. Cs(1) is bonded in a 9-coordinate geometry to one F(2), two equivalent F(3), three equivalent F(1), and three equivalent F(4) atoms. The Cs(1)-F(2) bond length is 3.22 Å. There is one shorter (3.25 Å) and one longer (3.36 Å) Cs(1)-F(3) bond length. There are a spread of Cs(1)-F(1) bond distances ranging from 3.06-3.26 Å. There is one shorter (2.96 Å) and two longer (3.20 Å) Cs(1)-F(4) bond lengths. Tl(1) is bonded to one F(1), one F(4), two equivalent F(2), and two equivalent F(3) atoms to form corner-sharing TlF6 octahedra. The corner-sharing octahedral tilt angles range from 32-42°. The Tl(1)-F(1) bond length is 2.09 Å. The Tl(1)-F(4) bond length is 2.10 Å. Both Tl(1)-F(2) bond lengths are 2.27 Å. Both Tl(1)-F(3) bond lengths are 2.29 Å. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted single-bond geometry to three equivalent Cs(1) and one Tl(1) atom. In the second F site, F(2) is bonded in a distorted bent 150 degrees geometry to one Cs(1) and two equivalent Tl(1) atoms. In the third F site, F(3) is bonded in a 4-coordinate geometry to two equivalent Cs(1) and two equivalent Tl(1) atoms. In the fourth F site, F(4) is bonded in a 4-coordinate geometry to three equivalent Cs(1) and one Tl(1) atom.