Dy2Ge2O7 crystallizes in the tetragonal P4_12_12 space group. Dy(1) is bonded to two equivalent O(1), two equivalent O(3), and three equivalent O(2) atoms to form distorted DyO7 pentagonal bipyramids that share corners with five equivalent Ge(1)O4 tetrahedra, edges with five equivalent Dy(1)O7 pentagonal bipyramids, and  an edgeedge with one Ge(1)O4 tetrahedra. Ge(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form GeO4 tetrahedra that share corners with five equivalent Dy(1)O7 pentagonal bipyramids,  a cornercorner with one Ge(1)O4 tetrahedra, and  an edgeedge with one Dy(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Dy(1) and one Ge(1) atom. In the second O site, O(2) is bonded to three equivalent Dy(1) and one Ge(1) atom to form a mixture of distorted corner and edge-sharing ODy3Ge trigonal pyramids. In the third O site, O(3) is bonded in a trigonal planar geometry to two equivalent Dy(1) and one Ge(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to two equivalent Ge(1) atoms.
Dy2Ge2O7 crystallizes in the tetragonal P4_12_12 space group. Dy(1) is bonded to two equivalent O(1), two equivalent O(3), and three equivalent O(2) atoms to form distorted DyO7 pentagonal bipyramids that share corners with five equivalent Ge(1)O4 tetrahedra, edges with five equivalent Dy(1)O7 pentagonal bipyramids, and  an edgeedge with one Ge(1)O4 tetrahedra. There is one shorter (2.24 Å) and one longer (2.38 Å) Dy(1)-O(1) bond length. There is one shorter (2.27 Å) and one longer (2.29 Å) Dy(1)-O(3) bond length. There are a spread of Dy(1)-O(2) bond distances ranging from 2.31-2.57 Å. Ge(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form GeO4 tetrahedra that share corners with five equivalent Dy(1)O7 pentagonal bipyramids,  a cornercorner with one Ge(1)O4 tetrahedra, and  an edgeedge with one Dy(1)O7 pentagonal bipyramid. The Ge(1)-O(1) bond length is 1.76 Å. The Ge(1)-O(2) bond length is 1.80 Å. The Ge(1)-O(3) bond length is 1.76 Å. The Ge(1)-O(4) bond length is 1.80 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Dy(1) and one Ge(1) atom. In the second O site, O(2) is bonded to three equivalent Dy(1) and one Ge(1) atom to form a mixture of distorted corner and edge-sharing ODy3Ge trigonal pyramids. In the third O site, O(3) is bonded in a trigonal planar geometry to two equivalent Dy(1) and one Ge(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to two equivalent Ge(1) atoms.