Rb3SiF7 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 10-coordinate geometry to two equivalent F(2), two equivalent F(3), and six equivalent F(1) atoms. In the second Rb site, Rb(2) is bonded to two equivalent F(2) and four equivalent F(3) atoms to form RbF6 octahedra that share corners with four equivalent Si(1)F6 octahedra and corners with six equivalent Rb(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 0-69°. Si(1) is bonded to two equivalent F(3) and four equivalent F(1) atoms to form SiF6 octahedra that share corners with four equivalent Rb(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 in a distorted single-bond geometry to three equivalent Rb(1) and one Si(1) atom. In the second F site, F(2) is bonded to two equivalent Rb(2) and four equivalent Rb(1) atoms to form corner-sharing FRb6 octahedra. The corner-sharing octahedral tilt angles range from 0-25°. In the third F site, F(3) is bonded in a single-bond geometry to two equivalent Rb(1), two equivalent Rb(2), and one Si(1) atom.
Rb3SiF7 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 10-coordinate geometry to two equivalent F(2), two equivalent F(3), and six equivalent F(1) atoms. Both Rb(1)-F(2) bond lengths are 2.86 Å. Both Rb(1)-F(3) bond lengths are 2.93 Å. There are two shorter (2.79 Å) and four longer (2.99 Å) Rb(1)-F(1) bond lengths. In the second Rb site, Rb(2) is bonded to two equivalent F(2) and four equivalent F(3) atoms to form RbF6 octahedra that share corners with four equivalent Si(1)F6 octahedra and corners with six equivalent Rb(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 0-69°. Both Rb(2)-F(2) bond lengths are 2.89 Å. All Rb(2)-F(3) bond lengths are 3.00 Å. Si(1) is bonded to two equivalent F(3) and four equivalent F(1) atoms to form SiF6 octahedra that share corners with four equivalent Rb(2)F6 octahedra. The corner-sharing octahedral tilt angles are 69°. Both Si(1)-F(3) bond lengths are 1.70 Å. All Si(1)-F(1) bond lengths are 1.70 Å. There are three inequivalent F sites. In the first F site, F(1) is bonded in a distorted single-bond geometry to three equivalent Rb(1) and one Si(1) atom. In the second F site, F(2) is bonded to two equivalent Rb(2) and four equivalent Rb(1) atoms to form corner-sharing FRb6 octahedra. The corner-sharing octahedral tilt angles range from 0-25°. In the third F site, F(3) is bonded in a single-bond geometry to two equivalent Rb(1), two equivalent Rb(2), and one Si(1) atom.