Materials Data on K3Rb by Materials Project
RbK3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Rb is bonded to twelve K atoms to form RbK12 cuboctahedra that share corners with six equivalent RbK12 cuboctahedra, corners with twelve KK8Rb4 cuboctahedra, edges with eighteen KK8Rb4 cuboctahedra, faces with eight equivalent RbK12 cuboctahedra, and faces with twelve KK8Rb4 cuboctahedra. All Rb–K bond lengths are 4.80 Å. There are two inequivalent K sites. In the first K site, K is bonded to four equivalent Rb and eight K atoms to form distorted KK8Rb4 cuboctahedra that share corners with four equivalent RbK12 cuboctahedra, corners with fourteen equivalent KK8Rb4 cuboctahedra, edges with six equivalent RbK12 cuboctahedra, edges with twelve KK8Rb4 cuboctahedra, faces with four equivalent RbK12 cuboctahedra, and faces with sixteen KK8Rb4 cuboctahedra. There are a spread of K–K bond distances ranging from 4.76–4.84 Å. In the second K site, K is bonded to four equivalent Rb and eight K atoms to form distorted KK8Rb4 cuboctahedra that share corners with four equivalent RbK12 cuboctahedra, corners with fourteen KK8Rb4 cuboctahedra, edges with six equivalent RbK12 cuboctahedra, edges with twelve KK8Rb4 cuboctahedra, faces with four equivalent RbK12 cuboctahedra, and faces with sixteen KK8Rb4 cuboctahedra. There are one shorter (4.76 Å) and one longer (4.84 Å) K–K bond lengths.