Sr2GeSe4 crystallizes in the orthorhombic Ama2 space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 7-coordinate geometry to one Se(1), two equivalent Se(2), and four equivalent Se(3) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and four equivalent Se(3) atoms. Ge(1) is bonded in a tetrahedral geometry to one Se(1), one Se(2), and two equivalent Se(3) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Sr(1), two equivalent Sr(2), and one Ge(1) atom to form SeSr3Ge trigonal pyramids that share corners with three equivalent Se(2)Sr4Ge trigonal bipyramids, corners with two equivalent Se(1)Sr3Ge trigonal pyramids, and edges with two equivalent Se(2)Sr4Ge trigonal bipyramids. In the second Se site, Se(2) is bonded to two equivalent Sr(1), two equivalent Sr(2), and one Ge(1) atom to form distorted SeSr4Ge trigonal bipyramids that share corners with four equivalent Se(2)Sr4Ge trigonal bipyramids, corners with three equivalent Se(1)Sr3Ge trigonal pyramids, and edges with two equivalent Se(1)Sr3Ge trigonal pyramids. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and one Ge(1) atom.
Sr2GeSe4 crystallizes in the orthorhombic Ama2 space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 7-coordinate geometry to one Se(1), two equivalent Se(2), and four equivalent Se(3) atoms. The Sr(1)-Se(1) bond length is 3.00 Å. There is one shorter (3.20 Å) and one longer (3.34 Å) Sr(1)-Se(2) bond length. There are two shorter (3.13 Å) and two longer (3.57 Å) Sr(1)-Se(3) bond lengths. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and four equivalent Se(3) atoms. Both Sr(2)-Se(1) bond lengths are 3.06 Å. Both Sr(2)-Se(2) bond lengths are 3.22 Å. There are two shorter (3.24 Å) and two longer (3.60 Å) Sr(2)-Se(3) bond lengths. Ge(1) is bonded in a tetrahedral geometry to one Se(1), one Se(2), and two equivalent Se(3) atoms. The Ge(1)-Se(1) bond length is 2.38 Å. The Ge(1)-Se(2) bond length is 2.37 Å. Both Ge(1)-Se(3) bond lengths are 2.36 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Sr(1), two equivalent Sr(2), and one Ge(1) atom to form SeSr3Ge trigonal pyramids that share corners with three equivalent Se(2)Sr4Ge trigonal bipyramids, corners with two equivalent Se(1)Sr3Ge trigonal pyramids, and edges with two equivalent Se(2)Sr4Ge trigonal bipyramids. In the second Se site, Se(2) is bonded to two equivalent Sr(1), two equivalent Sr(2), and one Ge(1) atom to form distorted SeSr4Ge trigonal bipyramids that share corners with four equivalent Se(2)Sr4Ge trigonal bipyramids, corners with three equivalent Se(1)Sr3Ge trigonal pyramids, and edges with two equivalent Se(1)Sr3Ge trigonal pyramids. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Sr(2), and one Ge(1) atom.