Materials Data on Sr3Ca by Materials Project
Sr3Ca is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Sr sites. In the first Sr site, Sr is bonded to eight Sr and four equivalent Ca atoms to form SrSr8Ca4 cuboctahedra that share corners with twelve equivalent SrSr8Ca4 cuboctahedra, edges with eight equivalent CaSr12 cuboctahedra, edges with sixteen SrSr8Ca4 cuboctahedra, faces with four equivalent CaSr12 cuboctahedra, and faces with fourteen SrSr8Ca4 cuboctahedra. There are four shorter (4.17 Å) and four longer (4.18 Å) Sr–Sr bond lengths. All Sr–Ca bond lengths are 4.17 Å. In the second Sr site, Sr is bonded to eight equivalent Sr and four equivalent Ca atoms to form SrSr8Ca4 cuboctahedra that share corners with four equivalent SrSr8Ca4 cuboctahedra, corners with eight equivalent CaSr12 cuboctahedra, edges with twenty-four SrSr8Ca4 cuboctahedra, faces with six equivalent CaSr12 cuboctahedra, and faces with twelve SrSr8Ca4 cuboctahedra. All Sr–Ca bond lengths are 4.18 Å. Ca is bonded to twelve Sr atoms to form CaSr12 cuboctahedra that share corners with four equivalent CaSr12 cuboctahedra, corners with eight equivalent SrSr8Ca4 cuboctahedra, edges with eight equivalent CaSr12 cuboctahedra, edges with sixteen equivalent SrSr8Ca4 cuboctahedra, faces with four equivalent CaSr12 cuboctahedra, and faces with fourteen SrSr8Ca4 cuboctahedra.