Cs3GeF7 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to two equivalent F(1), two equivalent F(3), and six equivalent F(2) atoms. In the second Cs site, Cs(2) is bonded to two equivalent F(1) and four equivalent F(3) atoms to form distorted CsF6 octahedra that share corners with four equivalent Ge(1)F6 octahedra and corners with six equivalent Cs(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 0-69°. Ge(1) is bonded to two equivalent F(3) and four equivalent F(2) atoms to form GeF6 octahedra that share corners with four equivalent Cs(2)F6 octahedra. The corner-sharing octahedral tilt angles are 69°. There are three inequivalent F sites. In the first F site, F(1) is bonded to two equivalent Cs(2) and four equivalent Cs(1) atoms to form corner-sharing FCs6 octahedra. The corner-sharing octahedral tilt angles range from 0-26°. In the second F site, F(2) is bonded in a distorted single-bond geometry to three equivalent Cs(1) and one Ge(1) atom. In the third F site, F(3) is bonded in a single-bond geometry to two equivalent Cs(1), two equivalent Cs(2), and one Ge(1) atom.
Cs3GeF7 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to two equivalent F(1), two equivalent F(3), and six equivalent F(2) atoms. Both Cs(1)-F(1) bond lengths are 3.03 Å. Both Cs(1)-F(3) bond lengths are 3.16 Å. There are two shorter (2.98 Å) and four longer (3.19 Å) Cs(1)-F(2) bond lengths. In the second Cs site, Cs(2) is bonded to two equivalent F(1) and four equivalent F(3) atoms to form distorted CsF6 octahedra that share corners with four equivalent Ge(1)F6 octahedra and corners with six equivalent Cs(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 0-69°. Both Cs(2)-F(1) bond lengths are 3.13 Å. All Cs(2)-F(3) bond lengths are 3.16 Å. Ge(1) is bonded to two equivalent F(3) and four equivalent F(2) atoms to form GeF6 octahedra that share corners with four equivalent Cs(2)F6 octahedra. The corner-sharing octahedral tilt angles are 69°. Both Ge(1)-F(3) bond lengths are 1.81 Å. All Ge(1)-F(2) bond lengths are 1.81 Å. There are three inequivalent F sites. In the first F site, F(1) is bonded to two equivalent Cs(2) and four equivalent Cs(1) atoms to form corner-sharing FCs6 octahedra. The corner-sharing octahedral tilt angles range from 0-26°. In the second F site, F(2) is bonded in a distorted single-bond geometry to three equivalent Cs(1) and one Ge(1) atom. In the third F site, F(3) is bonded in a single-bond geometry to two equivalent Cs(1), two equivalent Cs(2), and one Ge(1) atom.