Rb2MgF4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. Rb(1) is bonded in a 9-coordinate geometry to four equivalent F(1) and five equivalent F(2) atoms. Mg(1) is bonded to two equivalent F(2) and four equivalent F(1) atoms to form corner-sharing MgF6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent F sites. In the first F site, F(2) is bonded to five equivalent Rb(1) and one Mg(1) atom to form a mixture of distorted corner and edge-sharing FRb5Mg octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second F site, F(1) is bonded in a distorted linear geometry to four equivalent Rb(1) and two equivalent Mg(1) atoms.
Rb2MgF4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. Rb(1) is bonded in a 9-coordinate geometry to four equivalent F(1) and five equivalent F(2) atoms. All Rb(1)-F(1) bond lengths are 2.88 Å. There is one shorter (2.83 Å) and four longer (2.86 Å) Rb(1)-F(2) bond lengths. Mg(1) is bonded to two equivalent F(2) and four equivalent F(1) atoms to form corner-sharing MgF6 octahedra. The corner-sharing octahedra are not tilted. Both Mg(1)-F(2) bond lengths are 2.00 Å. All Mg(1)-F(1) bond lengths are 2.02 Å. There are two inequivalent F sites. In the first F site, F(2) is bonded to five equivalent Rb(1) and one Mg(1) atom to form a mixture of distorted corner and edge-sharing FRb5Mg octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second F site, F(1) is bonded in a distorted linear geometry to four equivalent Rb(1) and two equivalent Mg(1) atoms.