DOE OSTI2020
K3Sr is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded to eight K and four equivalent Sr atoms to form KK8Sr4 cuboctahedra that share corners with twelve equivalent KK8Sr4 cuboctahedra, edges with eight equivalent SrK12 cuboctahedra, edges with sixteen KK8Sr4 cuboctahedra, faces with four equivalent SrK12 cuboctahedra, and faces with fourteen KK8Sr4 cuboctahedra. There are four shorter (4.49 Å) and four longer (4.67 Å) K–K bond lengths. All K–Sr bond lengths are 4.67 Å. In the second K site, K is bonded to eight equivalent K and four equivalent Sr atoms to form distorted KK8Sr4 cuboctahedra that share corners with four equivalent KK8Sr4 cuboctahedra, corners with eight equivalent SrK12 cuboctahedra, edges with twenty-four KK8Sr4 cuboctahedra, faces with six equivalent SrK12 cuboctahedra, and faces with twelve KK8Sr4 cuboctahedra. All K–Sr bond lengths are 4.49 Å. Sr is bonded to twelve K atoms to form SrK12 cuboctahedra that share corners with four equivalent SrK12 cuboctahedra, corners with eight equivalent KK8Sr4 cuboctahedra, edges with eight equivalent SrK12 cuboctahedra, edges with sixteen equivalent KK8Sr4 cuboctahedra, faces with four equivalent SrK12 cuboctahedra, and faces with fourteen KK8Sr4 cuboctahedra.