SrPa3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Sr(1) is bonded to four equivalent Pa(2) and eight equivalent Pa(1) atoms to form SrPa12 cuboctahedra that share corners with four equivalent Sr(1)Pa12 cuboctahedra, corners with eight equivalent Pa(2)Sr4Pa8 cuboctahedra, edges with eight equivalent Sr(1)Pa12 cuboctahedra, edges with sixteen equivalent Pa(1)Sr4Pa8 cuboctahedra, faces with four equivalent Sr(1)Pa12 cuboctahedra, faces with six equivalent Pa(2)Sr4Pa8 cuboctahedra, and faces with eight equivalent Pa(1)Sr4Pa8 cuboctahedra. There are two inequivalent Pa sites. In the first Pa site, Pa(1) is bonded to four equivalent Sr(1), four equivalent Pa(1), and four equivalent Pa(2) atoms to form distorted PaSr4Pa8 cuboctahedra that share corners with twelve equivalent Pa(1)Sr4Pa8 cuboctahedra, edges with eight equivalent Sr(1)Pa12 cuboctahedra, edges with eight equivalent Pa(1)Sr4Pa8 cuboctahedra, edges with eight equivalent Pa(2)Sr4Pa8 cuboctahedra, faces with four equivalent Sr(1)Pa12 cuboctahedra, faces with four equivalent Pa(2)Sr4Pa8 cuboctahedra, and faces with ten equivalent Pa(1)Sr4Pa8 cuboctahedra. In the second Pa site, Pa(2) is bonded to four equivalent Sr(1) and eight equivalent Pa(1) atoms to form distorted PaSr4Pa8 cuboctahedra that share corners with four equivalent Pa(2)Sr4Pa8 cuboctahedra, corners with eight equivalent Sr(1)Pa12 cuboctahedra, edges with eight equivalent Pa(2)Sr4Pa8 cuboctahedra, edges with sixteen equivalent Pa(1)Sr4Pa8 cuboctahedra, faces with four equivalent Pa(2)Sr4Pa8 cuboctahedra, faces with six equivalent Sr(1)Pa12 cuboctahedra, and faces with eight equivalent Pa(1)Sr4Pa8 cuboctahedra.
SrPa3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Sr(1) is bonded to four equivalent Pa(2) and eight equivalent Pa(1) atoms to form SrPa12 cuboctahedra that share corners with four equivalent Sr(1)Pa12 cuboctahedra, corners with eight equivalent Pa(2)Sr4Pa8 cuboctahedra, edges with eight equivalent Sr(1)Pa12 cuboctahedra, edges with sixteen equivalent Pa(1)Sr4Pa8 cuboctahedra, faces with four equivalent Sr(1)Pa12 cuboctahedra, faces with six equivalent Pa(2)Sr4Pa8 cuboctahedra, and faces with eight equivalent Pa(1)Sr4Pa8 cuboctahedra. All Sr(1)-Pa(2) bond lengths are 3.39 Å. All Sr(1)-Pa(1) bond lengths are 3.37 Å. There are two inequivalent Pa sites. In the first Pa site, Pa(1) is bonded to four equivalent Sr(1), four equivalent Pa(1), and four equivalent Pa(2) atoms to form distorted PaSr4Pa8 cuboctahedra that share corners with twelve equivalent Pa(1)Sr4Pa8 cuboctahedra, edges with eight equivalent Sr(1)Pa12 cuboctahedra, edges with eight equivalent Pa(1)Sr4Pa8 cuboctahedra, edges with eight equivalent Pa(2)Sr4Pa8 cuboctahedra, faces with four equivalent Sr(1)Pa12 cuboctahedra, faces with four equivalent Pa(2)Sr4Pa8 cuboctahedra, and faces with ten equivalent Pa(1)Sr4Pa8 cuboctahedra. All Pa(1)-Pa(1) bond lengths are 3.39 Å. All Pa(1)-Pa(2) bond lengths are 3.37 Å. In the second Pa site, Pa(2) is bonded to four equivalent Sr(1) and eight equivalent Pa(1) atoms to form distorted PaSr4Pa8 cuboctahedra that share corners with four equivalent Pa(2)Sr4Pa8 cuboctahedra, corners with eight equivalent Sr(1)Pa12 cuboctahedra, edges with eight equivalent Pa(2)Sr4Pa8 cuboctahedra, edges with sixteen equivalent Pa(1)Sr4Pa8 cuboctahedra, faces with four equivalent Pa(2)Sr4Pa8 cuboctahedra, faces with six equivalent Sr(1)Pa12 cuboctahedra, and faces with eight equivalent Pa(1)Sr4Pa8 cuboctahedra.