Materials Data on K2RbAlBr6 by Materials Project

Abstract

RbK2AlBr6 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Rb1+ is bonded to six equivalent Br1- atoms to form RbBr6 octahedra that share corners with six equivalent AlBr6 octahedra and faces with eight equivalent KBr12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Rb–Br bond lengths are 3.23 Å. K1+ is bonded to twelve equivalent Br1- atoms to form distorted KBr12 cuboctahedra that share corners with twelve equivalent KBr12 cuboctahedra, faces with six equivalent KBr12 cuboctahedra, faces with four equivalent RbBr6 octahedra, and faces with four equivalent AlBr6 octahedra. All K–Br bond lengths are 4.08 Å. Al3+ is bonded to six equivalent Br1- atoms to form AlBr6 octahedra that share corners with six equivalent RbBr6 octahedra and faces with eight equivalent KBr12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Al–Br bond lengths are 2.52 Å. Br1- is bonded in a linear geometry to one Rb1+, four equivalent K1+, and one Al3+ atom.