Y2Ge2O7 crystallizes in the monoclinic C2/m space group. Y(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted YO6 pentagonal pyramids that share corners with six equivalent Ge(1)O4 tetrahedra and edges with three equivalent Y(1)O6 pentagonal pyramids. Ge(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form GeO4 tetrahedra that share corners with six equivalent Y(1)O6 pentagonal pyramids and  a cornercorner with one Ge(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Y(1) and one Ge(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Y(1) and one Ge(1) atom. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ge(1) atoms.
Y2Ge2O7 crystallizes in the monoclinic C2/m space group. Y(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted YO6 pentagonal pyramids that share corners with six equivalent Ge(1)O4 tetrahedra and edges with three equivalent Y(1)O6 pentagonal pyramids. Both Y(1)-O(2) bond lengths are 2.26 Å. There are two shorter (2.24 Å) and two longer (2.32 Å) Y(1)-O(1) bond lengths. Ge(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form GeO4 tetrahedra that share corners with six equivalent Y(1)O6 pentagonal pyramids and  a cornercorner with one Ge(1)O4 tetrahedra. The Ge(1)-O(2) bond length is 1.75 Å. The Ge(1)-O(3) bond length is 1.75 Å. Both Ge(1)-O(1) bond lengths are 1.75 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Y(1) and one Ge(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Y(1) and one Ge(1) atom. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ge(1) atoms.