Sr3(GeP2)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one P(1), one P(2), two equivalent P(3), and two equivalent P(4) atoms to form a mixture of distorted corner and edge-sharing SrP6 octahedra. The corner-sharing octahedral tilt angles range from 4-13°. In the second Sr site, Sr(2) is bonded to one P(3), one P(4), two equivalent P(1), and two equivalent P(2) atoms to form a mixture of corner and edge-sharing SrP6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. In the third Sr site, Sr(3) is bonded to one P(3), one P(4), two equivalent P(1), and two equivalent P(2) atoms to form a mixture of distorted corner and edge-sharing SrP6 octahedra. The corner-sharing octahedral tilt angles range from 3-10°. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 4-coordinate geometry to one Ge(2), one P(1), one P(2), and one P(3) atom. In the second Ge site, Ge(2) is bonded in a 4-coordinate geometry to one Ge(1), one P(3), and two equivalent P(4) atoms. There are four inequivalent P sites. In the first P site, P(4) is bonded to one Sr(2), one Sr(3), two equivalent Sr(1), and two equivalent Ge(2) atoms to form PSr4Ge2 octahedra that share corners with two equivalent P(3)Sr4Ge2 octahedra, corners with two equivalent P(1)Sr5Ge octahedra, corners with four equivalent P(2)Sr5Ge octahedra,  an edgeedge with one P(2)Sr5Ge octahedra, edges with two equivalent P(4)Sr4Ge2 octahedra, edges with two equivalent P(1)Sr5Ge octahedra, and edges with three equivalent P(3)Sr4Ge2 octahedra. The corner-sharing octahedral tilt angles range from 2-95°. In the second P site, P(1) is bonded to one Sr(1), two equivalent Sr(2), two equivalent Sr(3), and one Ge(1) atom to form PSr5Ge octahedra that share corners with two equivalent P(4)Sr4Ge2 octahedra, corners with two equivalent P(2)Sr5Ge octahedra, corners with three equivalent P(3)Sr4Ge2 octahedra, edges with two equivalent P(3)Sr4Ge2 octahedra, edges with two equivalent P(4)Sr4Ge2 octahedra, edges with two equivalent P(1)Sr5Ge octahedra, and edges with four equivalent P(2)Sr5Ge octahedra. The corner-sharing octahedral tilt angles range from 3-95°. In the third P site, P(2) is bonded to one Sr(1), two equivalent Sr(2), two equivalent Sr(3), and one Ge(1) atom to form PSr5Ge octahedra that share  a cornercorner with one P(3)Sr4Ge2 octahedra, corners with two equivalent P(1)Sr5Ge octahedra, corners with four equivalent P(4)Sr4Ge2 octahedra,  an edgeedge with one P(4)Sr4Ge2 octahedra, edges with two equivalent P(2)Sr5Ge octahedra, edges with three equivalent P(3)Sr4Ge2 octahedra, and edges with four equivalent P(1)Sr5Ge octahedra. The corner-sharing octahedral tilt angles range from 2-88°. In the fourth P site, P(3) is bonded to one Sr(2), one Sr(3), two equivalent Sr(1), one Ge(1), and one Ge(2) atom to form PSr4Ge2 octahedra that share  a cornercorner with one P(2)Sr5Ge octahedra, corners with two equivalent P(3)Sr4Ge2 octahedra, corners with two equivalent P(4)Sr4Ge2 octahedra, corners with three equivalent P(1)Sr5Ge octahedra, edges with two equivalent P(1)Sr5Ge octahedra, edges with three equivalent P(4)Sr4Ge2 octahedra, and edges with three equivalent P(2)Sr5Ge octahedra. The corner-sharing octahedral tilt angles range from 6-95°.
Sr3(GeP2)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one P(1), one P(2), two equivalent P(3), and two equivalent P(4) atoms to form a mixture of distorted corner and edge-sharing SrP6 octahedra. The corner-sharing octahedral tilt angles range from 4-13°. The Sr(1)-P(1) bond length is 3.10 Å. The Sr(1)-P(2) bond length is 3.05 Å. There is one shorter (3.14 Å) and one longer (3.29 Å) Sr(1)-P(3) bond length. There is one shorter (3.12 Å) and one longer (3.20 Å) Sr(1)-P(4) bond length. In the second Sr site, Sr(2) is bonded to one P(3), one P(4), two equivalent P(1), and two equivalent P(2) atoms to form a mixture of corner and edge-sharing SrP6 octahedra. The corner-sharing octahedral tilt angles range from 3-13°. The Sr(2)-P(3) bond length is 3.12 Å. The Sr(2)-P(4) bond length is 3.19 Å. There is one shorter (3.05 Å) and one longer (3.12 Å) Sr(2)-P(1) bond length. There is one shorter (3.08 Å) and one longer (3.10 Å) Sr(2)-P(2) bond length. In the third Sr site, Sr(3) is bonded to one P(3), one P(4), two equivalent P(1), and two equivalent P(2) atoms to form a mixture of distorted corner and edge-sharing SrP6 octahedra. The corner-sharing octahedral tilt angles range from 3-10°. The Sr(3)-P(3) bond length is 3.17 Å. The Sr(3)-P(4) bond length is 3.29 Å. There is one shorter (3.07 Å) and one longer (3.08 Å) Sr(3)-P(1) bond length. Both Sr(3)-P(2) bond lengths are 3.06 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 4-coordinate geometry to one Ge(2), one P(1), one P(2), and one P(3) atom. The Ge(1)-Ge(2) bond length is 2.46 Å. The Ge(1)-P(1) bond length is 2.33 Å. The Ge(1)-P(2) bond length is 2.31 Å. The Ge(1)-P(3) bond length is 2.41 Å. In the second Ge site, Ge(2) is bonded in a 4-coordinate geometry to one Ge(1), one P(3), and two equivalent P(4) atoms. The Ge(2)-P(3) bond length is 2.36 Å. Both Ge(2)-P(4) bond lengths are 2.39 Å. There are four inequivalent P sites. In the first P site, P(4) is bonded to one Sr(2), one Sr(3), two equivalent Sr(1), and two equivalent Ge(2) atoms to form PSr4Ge2 octahedra that share corners with two equivalent P(3)Sr4Ge2 octahedra, corners with two equivalent P(1)Sr5Ge octahedra, corners with four equivalent P(2)Sr5Ge octahedra,  an edgeedge with one P(2)Sr5Ge octahedra, edges with two equivalent P(4)Sr4Ge2 octahedra, edges with two equivalent P(1)Sr5Ge octahedra, and edges with three equivalent P(3)Sr4Ge2 octahedra. The corner-sharing octahedral tilt angles range from 2-95°. In the second P site, P(1) is bonded to one Sr(1), two equivalent Sr(2), two equivalent Sr(3), and one Ge(1) atom to form PSr5Ge octahedra that share corners with two equivalent P(4)Sr4Ge2 octahedra, corners with two equivalent P(2)Sr5Ge octahedra, corners with three equivalent P(3)Sr4Ge2 octahedra, edges with two equivalent P(3)Sr4Ge2 octahedra, edges with two equivalent P(4)Sr4Ge2 octahedra, edges with two equivalent P(1)Sr5Ge octahedra, and edges with four equivalent P(2)Sr5Ge octahedra. The corner-sharing octahedral tilt angles range from 3-95°. In the third P site, P(2) is bonded to one Sr(1), two equivalent Sr(2), two equivalent Sr(3), and one Ge(1) atom to form PSr5Ge octahedra that share  a cornercorner with one P(3)Sr4Ge2 octahedra, corners with two equivalent P(1)Sr5Ge octahedra, corners with four equivalent P(4)Sr4Ge2 octahedra,  an edgeedge with one P(4)Sr4Ge2 octahedra, edges with two equivalent P(2)Sr5Ge octahedra, edges with three equivalent P(3)Sr4Ge2 octahedra, and edges with four equivalent P(1)Sr5Ge octahedra. The corner-sharing octahedral tilt angles range from 2-88°. In the fourth P site, P(3) is bonded to one Sr(2), one Sr(3), two equivalent Sr(1), one Ge(1), and one Ge(2) atom to form PSr4Ge2 octahedra that share  a cornercorner with one P(2)Sr5Ge octahedra, corners with two equivalent P(3)Sr4Ge2 octahedra, corners with two equivalent P(4)Sr4Ge2 octahedra, corners with three equivalent P(1)Sr5Ge octahedra, edges with two equivalent P(1)Sr5Ge octahedra, edges with three equivalent P(4)Sr4Ge2 octahedra, and edges with three equivalent P(2)Sr5Ge octahedra. The corner-sharing octahedral tilt angles range from 6-95°.