Er2Pb2O7 crystallizes in the cubic Fd-3m space group. Er(1) is bonded in a body-centered cubic geometry to two equivalent O(2) and six equivalent O(1) atoms. Pb(1) is bonded to six equivalent O(1) atoms to form distorted corner-sharing PbO6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Er(1) and two equivalent Pb(1) atoms to form OEr2Pb2 tetrahedra that share corners with two equivalent O(2)Er4 tetrahedra, corners with twelve equivalent O(1)Er2Pb2 tetrahedra,  an edgeedge with one O(2)Er4 tetrahedra, and edges with four equivalent O(1)Er2Pb2 tetrahedra. In the second O site, O(2) is bonded to four equivalent Er(1) atoms to form OEr4 tetrahedra that share corners with four equivalent O(2)Er4 tetrahedra, corners with twelve equivalent O(1)Er2Pb2 tetrahedra, and edges with six equivalent O(1)Er2Pb2 tetrahedra.
Er2Pb2O7 crystallizes in the cubic Fd-3m space group. Er(1) is bonded in a body-centered cubic geometry to two equivalent O(2) and six equivalent O(1) atoms. Both Er(1)-O(2) bond lengths are 2.30 Å. All Er(1)-O(1) bond lengths are 2.46 Å. Pb(1) is bonded to six equivalent O(1) atoms to form distorted corner-sharing PbO6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Pb(1)-O(1) bond lengths are 2.15 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Er(1) and two equivalent Pb(1) atoms to form OEr2Pb2 tetrahedra that share corners with two equivalent O(2)Er4 tetrahedra, corners with twelve equivalent O(1)Er2Pb2 tetrahedra,  an edgeedge with one O(2)Er4 tetrahedra, and edges with four equivalent O(1)Er2Pb2 tetrahedra. In the second O site, O(2) is bonded to four equivalent Er(1) atoms to form OEr4 tetrahedra that share corners with four equivalent O(2)Er4 tetrahedra, corners with twelve equivalent O(1)Er2Pb2 tetrahedra, and edges with six equivalent O(1)Er2Pb2 tetrahedra.