Sm2Hf2O7 crystallizes in the cubic Fd-3m space group. Sm(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(2) and six equivalent O(1) atoms. Hf(1) is bonded to six equivalent O(1) atoms to form corner-sharing HfO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sm(1) and two equivalent Hf(1) atoms to form distorted OSm2Hf2 tetrahedra that share corners with two equivalent O(2)Sm4 tetrahedra, corners with twelve equivalent O(1)Sm2Hf2 tetrahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and edges with four equivalent O(1)Sm2Hf2 tetrahedra. In the second O site, O(2) is bonded to four equivalent Sm(1) atoms to form OSm4 tetrahedra that share corners with four equivalent O(2)Sm4 tetrahedra, corners with twelve equivalent O(1)Sm2Hf2 tetrahedra, and edges with six equivalent O(1)Sm2Hf2 tetrahedra.
Sm2Hf2O7 crystallizes in the cubic Fd-3m space group. Sm(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(2) and six equivalent O(1) atoms. Both Sm(1)-O(2) bond lengths are 2.29 Å. All Sm(1)-O(1) bond lengths are 2.56 Å. Hf(1) is bonded to six equivalent O(1) atoms to form corner-sharing HfO6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Hf(1)-O(1) bond lengths are 2.07 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sm(1) and two equivalent Hf(1) atoms to form distorted OSm2Hf2 tetrahedra that share corners with two equivalent O(2)Sm4 tetrahedra, corners with twelve equivalent O(1)Sm2Hf2 tetrahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and edges with four equivalent O(1)Sm2Hf2 tetrahedra. In the second O site, O(2) is bonded to four equivalent Sm(1) atoms to form OSm4 tetrahedra that share corners with four equivalent O(2)Sm4 tetrahedra, corners with twelve equivalent O(1)Sm2Hf2 tetrahedra, and edges with six equivalent O(1)Sm2Hf2 tetrahedra.