CaTb3 crystallizes in the tetragonal I4/mmm space group. Ca(1) is bonded to four equivalent Tb(2) and eight equivalent Tb(1) atoms to form CaTb12 cuboctahedra that share corners with four equivalent Ca(1)Tb12 cuboctahedra, corners with eight equivalent Tb(2)Ca4Tb8 cuboctahedra, edges with eight equivalent Ca(1)Tb12 cuboctahedra, edges with sixteen equivalent Tb(1)Ca4Tb8 cuboctahedra, faces with four equivalent Ca(1)Tb12 cuboctahedra, faces with six equivalent Tb(2)Ca4Tb8 cuboctahedra, and faces with eight equivalent Tb(1)Ca4Tb8 cuboctahedra. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to four equivalent Ca(1), four equivalent Tb(1), and four equivalent Tb(2) atoms to form TbCa4Tb8 cuboctahedra that share corners with twelve equivalent Tb(1)Ca4Tb8 cuboctahedra, edges with eight equivalent Ca(1)Tb12 cuboctahedra, edges with eight equivalent Tb(1)Ca4Tb8 cuboctahedra, edges with eight equivalent Tb(2)Ca4Tb8 cuboctahedra, faces with four equivalent Ca(1)Tb12 cuboctahedra, faces with four equivalent Tb(2)Ca4Tb8 cuboctahedra, and faces with ten equivalent Tb(1)Ca4Tb8 cuboctahedra. In the second Tb site, Tb(2) is bonded to four equivalent Ca(1) and eight equivalent Tb(1) atoms to form TbCa4Tb8 cuboctahedra that share corners with four equivalent Tb(2)Ca4Tb8 cuboctahedra, corners with eight equivalent Ca(1)Tb12 cuboctahedra, edges with eight equivalent Tb(2)Ca4Tb8 cuboctahedra, edges with sixteen equivalent Tb(1)Ca4Tb8 cuboctahedra, faces with four equivalent Tb(2)Ca4Tb8 cuboctahedra, faces with six equivalent Ca(1)Tb12 cuboctahedra, and faces with eight equivalent Tb(1)Ca4Tb8 cuboctahedra.
CaTb3 crystallizes in the tetragonal I4/mmm space group. Ca(1) is bonded to four equivalent Tb(2) and eight equivalent Tb(1) atoms to form CaTb12 cuboctahedra that share corners with four equivalent Ca(1)Tb12 cuboctahedra, corners with eight equivalent Tb(2)Ca4Tb8 cuboctahedra, edges with eight equivalent Ca(1)Tb12 cuboctahedra, edges with sixteen equivalent Tb(1)Ca4Tb8 cuboctahedra, faces with four equivalent Ca(1)Tb12 cuboctahedra, faces with six equivalent Tb(2)Ca4Tb8 cuboctahedra, and faces with eight equivalent Tb(1)Ca4Tb8 cuboctahedra. All Ca(1)-Tb(2) bond lengths are 3.62 Å. All Ca(1)-Tb(1) bond lengths are 3.61 Å. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to four equivalent Ca(1), four equivalent Tb(1), and four equivalent Tb(2) atoms to form TbCa4Tb8 cuboctahedra that share corners with twelve equivalent Tb(1)Ca4Tb8 cuboctahedra, edges with eight equivalent Ca(1)Tb12 cuboctahedra, edges with eight equivalent Tb(1)Ca4Tb8 cuboctahedra, edges with eight equivalent Tb(2)Ca4Tb8 cuboctahedra, faces with four equivalent Ca(1)Tb12 cuboctahedra, faces with four equivalent Tb(2)Ca4Tb8 cuboctahedra, and faces with ten equivalent Tb(1)Ca4Tb8 cuboctahedra. All Tb(1)-Tb(1) bond lengths are 3.62 Å. All Tb(1)-Tb(2) bond lengths are 3.61 Å. In the second Tb site, Tb(2) is bonded to four equivalent Ca(1) and eight equivalent Tb(1) atoms to form TbCa4Tb8 cuboctahedra that share corners with four equivalent Tb(2)Ca4Tb8 cuboctahedra, corners with eight equivalent Ca(1)Tb12 cuboctahedra, edges with eight equivalent Tb(2)Ca4Tb8 cuboctahedra, edges with sixteen equivalent Tb(1)Ca4Tb8 cuboctahedra, faces with four equivalent Tb(2)Ca4Tb8 cuboctahedra, faces with six equivalent Ca(1)Tb12 cuboctahedra, and faces with eight equivalent Tb(1)Ca4Tb8 cuboctahedra.