Y2Pt2Se7 crystallizes in the cubic Fd-3m space group. Y(1) is bonded in a body-centered cubic geometry to two equivalent Se(2) and six equivalent Se(1) atoms. Pt(1) is bonded to six equivalent Se(1) atoms to form corner-sharing PtSe6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Y(1) and two equivalent Pt(1) atoms to form SeY2Pt2 tetrahedra that share corners with two equivalent Se(2)Y4 tetrahedra, corners with twelve equivalent Se(1)Y2Pt2 tetrahedra,  an edgeedge with one Se(2)Y4 tetrahedra, and edges with four equivalent Se(1)Y2Pt2 tetrahedra. In the second Se site, Se(2) is bonded to four equivalent Y(1) atoms to form SeY4 tetrahedra that share corners with four equivalent Se(2)Y4 tetrahedra, corners with twelve equivalent Se(1)Y2Pt2 tetrahedra, and edges with six equivalent Se(1)Y2Pt2 tetrahedra.
Y2Pt2Se7 crystallizes in the cubic Fd-3m space group. Y(1) is bonded in a body-centered cubic geometry to two equivalent Se(2) and six equivalent Se(1) atoms. Both Y(1)-Se(2) bond lengths are 2.78 Å. All Y(1)-Se(1) bond lengths are 3.08 Å. Pt(1) is bonded to six equivalent Se(1) atoms to form corner-sharing PtSe6 octahedra. The corner-sharing octahedral tilt angles are 53°. All Pt(1)-Se(1) bond lengths are 2.54 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Y(1) and two equivalent Pt(1) atoms to form SeY2Pt2 tetrahedra that share corners with two equivalent Se(2)Y4 tetrahedra, corners with twelve equivalent Se(1)Y2Pt2 tetrahedra,  an edgeedge with one Se(2)Y4 tetrahedra, and edges with four equivalent Se(1)Y2Pt2 tetrahedra. In the second Se site, Se(2) is bonded to four equivalent Y(1) atoms to form SeY4 tetrahedra that share corners with four equivalent Se(2)Y4 tetrahedra, corners with twelve equivalent Se(1)Y2Pt2 tetrahedra, and edges with six equivalent Se(1)Y2Pt2 tetrahedra.