Sr3(AlGe2)2 is Magnesium tetraboride-derived structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to two equivalent Al(1), three equivalent Ge(1), and four equivalent Ge(2) atoms. In the second Sr site, Sr(2) is bonded to two equivalent Ge(2) and four equivalent Ge(1) atoms to form distorted edge-sharing SrGe6 octahedra. Al(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Ge(1), and three equivalent Ge(2) atoms. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to two equivalent Sr(2), three equivalent Sr(1), one Al(1), and two equivalent Ge(1) atoms. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to one Sr(2), four equivalent Sr(1), and three equivalent Al(1) atoms.
Sr3(AlGe2)2 is Magnesium tetraboride-derived structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to two equivalent Al(1), three equivalent Ge(1), and four equivalent Ge(2) atoms. Both Sr(1)-Al(1) bond lengths are 3.29 Å. There is one shorter (3.08 Å) and two longer (3.36 Å) Sr(1)-Ge(1) bond lengths. There are two shorter (3.30 Å) and two longer (3.36 Å) Sr(1)-Ge(2) bond lengths. In the second Sr site, Sr(2) is bonded to two equivalent Ge(2) and four equivalent Ge(1) atoms to form distorted edge-sharing SrGe6 octahedra. Both Sr(2)-Ge(2) bond lengths are 3.26 Å. All Sr(2)-Ge(1) bond lengths are 3.31 Å. Al(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Ge(1), and three equivalent Ge(2) atoms. The Al(1)-Ge(1) bond length is 2.65 Å. There are two shorter (2.52 Å) and one longer (2.66 Å) Al(1)-Ge(2) bond length. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to two equivalent Sr(2), three equivalent Sr(1), one Al(1), and two equivalent Ge(1) atoms. Both Ge(1)-Ge(1) bond lengths are 2.64 Å. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to one Sr(2), four equivalent Sr(1), and three equivalent Al(1) atoms.