Ca10(Al2Ge3)3 crystallizes in the trigonal R-3m space group. There are five inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms. In the second Ca site, Ca(2) is bonded in a distorted see-saw-like geometry to two equivalent Al(2), two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms. In the third Ca site, Ca(3) is bonded in a 7-coordinate geometry to two equivalent Al(2), one Ge(3), two equivalent Ge(1), and two equivalent Ge(2) atoms. In the fourth Ca site, Ca(4) is bonded to six equivalent Al(1) and six equivalent Ge(3) atoms to form distorted CaAl6Ge6 cuboctahedra that share edges with six equivalent Al(1)CaGe4 tetrahedra. In the fifth Ca site, Ca(5) is bonded in a distorted cuboctahedral geometry to six equivalent Al(2) and six equivalent Ge(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one Ca(4), two equivalent Ge(1), and two equivalent Ge(3) atoms to form distorted AlCaGe4 tetrahedra that share corners with three equivalent Al(1)CaGe4 tetrahedra,  an edgeedge with one Ca(4)Al6Ge6 cuboctahedra, and edges with three equivalent Al(1)CaGe4 tetrahedra. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to one Ca(5), two equivalent Ca(2), two equivalent Ca(3), two equivalent Al(2), one Ge(1), and two equivalent Ge(2) atoms. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 9-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), one Al(2), and two equivalent Al(1) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to one Ca(5), two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), and two equivalent Al(2) atoms. In the third Ge site, Ge(3) is bonded in a 8-coordinate geometry to one Ca(3), one Ca(4), two equivalent Ca(1), two equivalent Ca(2), and two equivalent Al(1) atoms.
Ca10(Al2Ge3)3 crystallizes in the trigonal R-3m space group. There are five inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms. Both Ca(1)-Ge(1) bond lengths are 3.41 Å. Both Ca(1)-Ge(2) bond lengths are 3.02 Å. Both Ca(1)-Ge(3) bond lengths are 3.17 Å. In the second Ca site, Ca(2) is bonded in a distorted see-saw-like geometry to two equivalent Al(2), two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms. Both Ca(2)-Al(2) bond lengths are 3.50 Å. Both Ca(2)-Ge(1) bond lengths are 3.06 Å. Both Ca(2)-Ge(2) bond lengths are 3.56 Å. Both Ca(2)-Ge(3) bond lengths are 3.05 Å. In the third Ca site, Ca(3) is bonded in a 7-coordinate geometry to two equivalent Al(2), one Ge(3), two equivalent Ge(1), and two equivalent Ge(2) atoms. Both Ca(3)-Al(2) bond lengths are 3.14 Å. The Ca(3)-Ge(3) bond length is 3.17 Å. Both Ca(3)-Ge(1) bond lengths are 2.91 Å. There is one shorter (3.10 Å) and one longer (3.33 Å) Ca(3)-Ge(2) bond length. In the fourth Ca site, Ca(4) is bonded to six equivalent Al(1) and six equivalent Ge(3) atoms to form distorted CaAl6Ge6 cuboctahedra that share edges with six equivalent Al(1)CaGe4 tetrahedra. All Ca(4)-Al(1) bond lengths are 3.54 Å. All Ca(4)-Ge(3) bond lengths are 3.31 Å. In the fifth Ca site, Ca(5) is bonded in a distorted cuboctahedral geometry to six equivalent Al(2) and six equivalent Ge(2) atoms. All Ca(5)-Al(2) bond lengths are 3.49 Å. All Ca(5)-Ge(2) bond lengths are 3.33 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one Ca(4), two equivalent Ge(1), and two equivalent Ge(3) atoms to form distorted AlCaGe4 tetrahedra that share corners with three equivalent Al(1)CaGe4 tetrahedra,  an edgeedge with one Ca(4)Al6Ge6 cuboctahedra, and edges with three equivalent Al(1)CaGe4 tetrahedra. There is one shorter (2.61 Å) and one longer (2.66 Å) Al(1)-Ge(1) bond length. Both Al(1)-Ge(3) bond lengths are 2.54 Å. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to one Ca(5), two equivalent Ca(2), two equivalent Ca(3), two equivalent Al(2), one Ge(1), and two equivalent Ge(2) atoms. Both Al(2)-Al(2) bond lengths are 3.00 Å. The Al(2)-Ge(1) bond length is 2.84 Å. Both Al(2)-Ge(2) bond lengths are 2.53 Å. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 9-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), one Al(2), and two equivalent Al(1) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to one Ca(5), two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), and two equivalent Al(2) atoms. In the third Ge site, Ge(3) is bonded in a 8-coordinate geometry to one Ca(3), one Ca(4), two equivalent Ca(1), two equivalent Ca(2), and two equivalent Al(1) atoms.