RbTlF3 is (Cubic) Perovskite structured and crystallizes in the monoclinic Cm space group. Rb(1) is bonded to four equivalent F(2) and eight equivalent F(1) atoms to form distorted RbF12 cuboctahedra that share corners with twelve equivalent Rb(1)F12 cuboctahedra, faces with six equivalent Rb(1)F12 cuboctahedra, and faces with eight equivalent Tl(1)F6 octahedra. Tl(1) is bonded to two equivalent F(2) and four equivalent F(1) atoms to form TlF6 octahedra that share corners with six equivalent Tl(1)F6 octahedra and faces with eight equivalent Rb(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-4°. There are two inequivalent F sites. In the first F site, F(1) is bonded in a distorted linear geometry to four equivalent Rb(1) and two equivalent Tl(1) atoms. In the second F site, F(2) is bonded in a distorted linear geometry to four equivalent Rb(1) and two equivalent Tl(1) atoms.
RbTlF3 is (Cubic) Perovskite structured and crystallizes in the monoclinic Cm space group. Rb(1) is bonded to four equivalent F(2) and eight equivalent F(1) atoms to form distorted RbF12 cuboctahedra that share corners with twelve equivalent Rb(1)F12 cuboctahedra, faces with six equivalent Rb(1)F12 cuboctahedra, and faces with eight equivalent Tl(1)F6 octahedra. There are a spread of Rb(1)-F(2) bond distances ranging from 3.26-3.48 Å. There are a spread of Rb(1)-F(1) bond distances ranging from 3.31-3.38 Å. Tl(1) is bonded to two equivalent F(2) and four equivalent F(1) atoms to form TlF6 octahedra that share corners with six equivalent Tl(1)F6 octahedra and faces with eight equivalent Rb(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-4°. There is one shorter (2.37 Å) and one longer (2.38 Å) Tl(1)-F(2) bond length. There are two shorter (2.37 Å) and two longer (2.38 Å) Tl(1)-F(1) bond lengths. There are two inequivalent F sites. In the first F site, F(1) is bonded in a distorted linear geometry to four equivalent Rb(1) and two equivalent Tl(1) atoms. In the second F site, F(2) is bonded in a distorted linear geometry to four equivalent Rb(1) and two equivalent Tl(1) atoms.