SrCa3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Sr(1) is bonded to four equivalent Ca(2) and eight equivalent Ca(1) atoms to form SrCa12 cuboctahedra that share corners with four equivalent Sr(1)Ca12 cuboctahedra, corners with eight equivalent Ca(2)Sr4Ca8 cuboctahedra, edges with eight equivalent Sr(1)Ca12 cuboctahedra, edges with sixteen equivalent Ca(1)Sr4Ca8 cuboctahedra, faces with four equivalent Sr(1)Ca12 cuboctahedra, faces with six equivalent Ca(2)Sr4Ca8 cuboctahedra, and faces with eight equivalent Ca(1)Sr4Ca8 cuboctahedra. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to four equivalent Sr(1), four equivalent Ca(1), and four equivalent Ca(2) atoms to form CaSr4Ca8 cuboctahedra that share corners with twelve equivalent Ca(1)Sr4Ca8 cuboctahedra, edges with eight equivalent Sr(1)Ca12 cuboctahedra, edges with eight equivalent Ca(1)Sr4Ca8 cuboctahedra, edges with eight equivalent Ca(2)Sr4Ca8 cuboctahedra, faces with four equivalent Sr(1)Ca12 cuboctahedra, faces with four equivalent Ca(2)Sr4Ca8 cuboctahedra, and faces with ten equivalent Ca(1)Sr4Ca8 cuboctahedra. In the second Ca site, Ca(2) is bonded to four equivalent Sr(1) and eight equivalent Ca(1) atoms to form CaSr4Ca8 cuboctahedra that share corners with four equivalent Ca(2)Sr4Ca8 cuboctahedra, corners with eight equivalent Sr(1)Ca12 cuboctahedra, edges with eight equivalent Ca(2)Sr4Ca8 cuboctahedra, edges with sixteen equivalent Ca(1)Sr4Ca8 cuboctahedra, faces with four equivalent Ca(2)Sr4Ca8 cuboctahedra, faces with six equivalent Sr(1)Ca12 cuboctahedra, and faces with eight equivalent Ca(1)Sr4Ca8 cuboctahedra.
SrCa3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Sr(1) is bonded to four equivalent Ca(2) and eight equivalent Ca(1) atoms to form SrCa12 cuboctahedra that share corners with four equivalent Sr(1)Ca12 cuboctahedra, corners with eight equivalent Ca(2)Sr4Ca8 cuboctahedra, edges with eight equivalent Sr(1)Ca12 cuboctahedra, edges with sixteen equivalent Ca(1)Sr4Ca8 cuboctahedra, faces with four equivalent Sr(1)Ca12 cuboctahedra, faces with six equivalent Ca(2)Sr4Ca8 cuboctahedra, and faces with eight equivalent Ca(1)Sr4Ca8 cuboctahedra. All Sr(1)-Ca(2) bond lengths are 4.05 Å. All Sr(1)-Ca(1) bond lengths are 4.03 Å. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to four equivalent Sr(1), four equivalent Ca(1), and four equivalent Ca(2) atoms to form CaSr4Ca8 cuboctahedra that share corners with twelve equivalent Ca(1)Sr4Ca8 cuboctahedra, edges with eight equivalent Sr(1)Ca12 cuboctahedra, edges with eight equivalent Ca(1)Sr4Ca8 cuboctahedra, edges with eight equivalent Ca(2)Sr4Ca8 cuboctahedra, faces with four equivalent Sr(1)Ca12 cuboctahedra, faces with four equivalent Ca(2)Sr4Ca8 cuboctahedra, and faces with ten equivalent Ca(1)Sr4Ca8 cuboctahedra. All Ca(1)-Ca(1) bond lengths are 4.05 Å. All Ca(1)-Ca(2) bond lengths are 4.03 Å. In the second Ca site, Ca(2) is bonded to four equivalent Sr(1) and eight equivalent Ca(1) atoms to form CaSr4Ca8 cuboctahedra that share corners with four equivalent Ca(2)Sr4Ca8 cuboctahedra, corners with eight equivalent Sr(1)Ca12 cuboctahedra, edges with eight equivalent Ca(2)Sr4Ca8 cuboctahedra, edges with sixteen equivalent Ca(1)Sr4Ca8 cuboctahedra, faces with four equivalent Ca(2)Sr4Ca8 cuboctahedra, faces with six equivalent Sr(1)Ca12 cuboctahedra, and faces with eight equivalent Ca(1)Sr4Ca8 cuboctahedra.