Be2Sm2GeO7 crystallizes in the tetragonal P-42_1m space group. Be(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form BeO4 tetrahedra that share  a cornercorner with one Be(1)O4 tetrahedra and corners with two equivalent Ge(1)O4 tetrahedra. Sm(1) is bonded in a 8-coordinate geometry to one O(2), three equivalent O(3), and four equivalent O(1) atoms. Ge(1) is bonded to four equivalent O(1) atoms to form GeO4 tetrahedra that share corners with four equivalent Be(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Sm(1), and one Ge(1) atom. In the second O site, O(2) is bonded to two equivalent Be(1) and two equivalent Sm(1) atoms to form a mixture of distorted corner and edge-sharing OSm2Be2 tetrahedra. In the third O site, O(3) is bonded to one Be(1) and three equivalent Sm(1) atoms to form distorted OSm3Be tetrahedra that share corners with two equivalent O(2)Sm2Be2 tetrahedra, corners with four equivalent O(3)Sm3Be tetrahedra,  an edgeedge with one O(2)Sm2Be2 tetrahedra, and  an edgeedge with one O(3)Sm3Be tetrahedra.
Be2Sm2GeO7 crystallizes in the tetragonal P-42_1m space group. Be(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form BeO4 tetrahedra that share  a cornercorner with one Be(1)O4 tetrahedra and corners with two equivalent Ge(1)O4 tetrahedra. The Be(1)-O(2) bond length is 1.58 Å. The Be(1)-O(3) bond length is 1.59 Å. Both Be(1)-O(1) bond lengths are 1.72 Å. Sm(1) is bonded in a 8-coordinate geometry to one O(2), three equivalent O(3), and four equivalent O(1) atoms. The Sm(1)-O(2) bond length is 2.34 Å. There is one shorter (2.39 Å) and two longer (2.51 Å) Sm(1)-O(3) bond lengths. There are two shorter (2.43 Å) and two longer (2.64 Å) Sm(1)-O(1) bond lengths. Ge(1) is bonded to four equivalent O(1) atoms to form GeO4 tetrahedra that share corners with four equivalent Be(1)O4 tetrahedra. All Ge(1)-O(1) bond lengths are 1.77 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Be(1), two equivalent Sm(1), and one Ge(1) atom. In the second O site, O(2) is bonded to two equivalent Be(1) and two equivalent Sm(1) atoms to form a mixture of distorted corner and edge-sharing OSm2Be2 tetrahedra. In the third O site, O(3) is bonded to one Be(1) and three equivalent Sm(1) atoms to form distorted OSm3Be tetrahedra that share corners with two equivalent O(2)Sm2Be2 tetrahedra, corners with four equivalent O(3)Sm3Be tetrahedra,  an edgeedge with one O(2)Sm2Be2 tetrahedra, and  an edgeedge with one O(3)Sm3Be tetrahedra.