Y2Hf2O7 crystallizes in the tetragonal P4_12_12 space group. Y(1) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent O(3), and three equivalent O(2) atoms. Hf(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form a mixture of distorted corner and edge-sharing HfO5 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Y(1) and two equivalent Hf(1) atoms to form distorted OY2Hf2 trigonal pyramids that share corners with two equivalent O(2)Y3Hf tetrahedra, corners with two equivalent O(1)Y2Hf2 trigonal pyramids, edges with three equivalent O(2)Y3Hf tetrahedra, and  an edgeedge with one O(1)Y2Hf2 trigonal pyramid. In the second O site, O(2) is bonded to three equivalent Y(1) and one Hf(1) atom to form distorted OY3Hf tetrahedra that share corners with four equivalent O(2)Y3Hf tetrahedra, corners with two equivalent O(1)Y2Hf2 trigonal pyramids,  an edgeedge with one O(2)Y3Hf tetrahedra, and edges with three equivalent O(1)Y2Hf2 trigonal pyramids. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Y(1) and one Hf(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Hf(1) atoms.
Y2Hf2O7 crystallizes in the tetragonal P4_12_12 space group. Y(1) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent O(3), and three equivalent O(2) atoms. There is one shorter (2.34 Å) and one longer (2.48 Å) Y(1)-O(1) bond length. There is one shorter (2.21 Å) and one longer (2.27 Å) Y(1)-O(3) bond length. There are a spread of Y(1)-O(2) bond distances ranging from 2.35-2.58 Å. Hf(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form a mixture of distorted corner and edge-sharing HfO5 trigonal bipyramids. The Hf(1)-O(2) bond length is 1.98 Å. The Hf(1)-O(3) bond length is 2.01 Å. The Hf(1)-O(4) bond length is 1.98 Å. There is one shorter (2.01 Å) and one longer (2.27 Å) Hf(1)-O(1) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Y(1) and two equivalent Hf(1) atoms to form distorted OY2Hf2 trigonal pyramids that share corners with two equivalent O(2)Y3Hf tetrahedra, corners with two equivalent O(1)Y2Hf2 trigonal pyramids, edges with three equivalent O(2)Y3Hf tetrahedra, and  an edgeedge with one O(1)Y2Hf2 trigonal pyramid. In the second O site, O(2) is bonded to three equivalent Y(1) and one Hf(1) atom to form distorted OY3Hf tetrahedra that share corners with four equivalent O(2)Y3Hf tetrahedra, corners with two equivalent O(1)Y2Hf2 trigonal pyramids,  an edgeedge with one O(2)Y3Hf tetrahedra, and edges with three equivalent O(1)Y2Hf2 trigonal pyramids. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Y(1) and one Hf(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Hf(1) atoms.