DOE OSTI2020
CsSr3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cs is bonded to twelve Sr atoms to form CsSr12 cuboctahedra that share corners with four equivalent CsSr12 cuboctahedra, corners with eight equivalent SrCs4Sr8 cuboctahedra, edges with eight equivalent CsSr12 cuboctahedra, edges with sixteen equivalent SrCs4Sr8 cuboctahedra, faces with four equivalent CsSr12 cuboctahedra, and faces with fourteen SrCs4Sr8 cuboctahedra. There are eight shorter (4.45 Å) and four longer (4.50 Å) Cs–Sr bond lengths. There are two inequivalent Sr sites. In the first Sr site, Sr is bonded to four equivalent Cs and eight Sr atoms to form SrCs4Sr8 cuboctahedra that share corners with twelve equivalent SrCs4Sr8 cuboctahedra, edges with eight equivalent CsSr12 cuboctahedra, edges with sixteen SrCs4Sr8 cuboctahedra, faces with four equivalent CsSr12 cuboctahedra, and faces with fourteen SrCs4Sr8 cuboctahedra. There are four shorter (4.45 Å) and four longer (4.50 Å) Sr–Sr bond lengths. In the second Sr site, Sr is bonded to four equivalent Cs and eight equivalent Sr atoms to form SrCs4Sr8 cuboctahedra that share corners with four equivalent SrCs4Sr8 cuboctahedra, corners with eight equivalent CsSr12 cuboctahedra, edges with twenty-four SrCs4Sr8 cuboctahedra, faces with six equivalent CsSr12 cuboctahedra, and faces with twelve SrCs4Sr8 cuboctahedra.