DOE OSTI2020
Rb3BrF12 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Rb sites. In the first Rb site, Rb is bonded in a 8-coordinate geometry to two equivalent Br and eight F atoms. Both Rb–Br bond lengths are 3.76 Å. There are four shorter (2.96 Å) and four longer (3.21 Å) Rb–F bond lengths. In the second Rb site, Rb is bonded to two equivalent Br and six F atoms to form distorted corner-sharing RbBr2F6 hexagonal bipyramids. Both Rb–Br bond lengths are 3.43 Å. There are a spread of Rb–F bond distances ranging from 2.69–2.94 Å. Br is bonded to six Rb atoms to form corner-sharing BrRb6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three inequivalent F sites. In the first F site, F is bonded in a bent 120 degrees geometry to one Rb and one F atom. The F–F bond length is 1.43 Å. In the second F site, F is bonded in a 2-coordinate geometry to two Rb and one F atom. The F–F bond length is 1.90 Å. In the third F site, F is bonded in a 3-coordinate geometry to two Rb and two F atoms. The F–F bond length is 1.76 Å.