Hg2GeSe4 crystallizes in the tetragonal I-4 space group. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to four equivalent Se(1) atoms to form HgSe4 tetrahedra that share corners with four equivalent Hg(2)Se4 tetrahedra and corners with four equivalent Ge(1)Se4 tetrahedra. In the second Hg site, Hg(2) is bonded to four equivalent Se(1) atoms to form HgSe4 tetrahedra that share corners with four equivalent Hg(1)Se4 tetrahedra and corners with four equivalent Ge(1)Se4 tetrahedra. Ge(1) is bonded to four equivalent Se(1) atoms to form GeSe4 tetrahedra that share corners with four equivalent Hg(1)Se4 tetrahedra and corners with four equivalent Hg(2)Se4 tetrahedra. Se(1) is bonded in a trigonal non-coplanar geometry to one Hg(1), one Hg(2), and one Ge(1) atom.
Hg2GeSe4 crystallizes in the tetragonal I-4 space group. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to four equivalent Se(1) atoms to form HgSe4 tetrahedra that share corners with four equivalent Hg(2)Se4 tetrahedra and corners with four equivalent Ge(1)Se4 tetrahedra. All Hg(1)-Se(1) bond lengths are 2.69 Å. In the second Hg site, Hg(2) is bonded to four equivalent Se(1) atoms to form HgSe4 tetrahedra that share corners with four equivalent Hg(1)Se4 tetrahedra and corners with four equivalent Ge(1)Se4 tetrahedra. All Hg(2)-Se(1) bond lengths are 2.71 Å. Ge(1) is bonded to four equivalent Se(1) atoms to form GeSe4 tetrahedra that share corners with four equivalent Hg(1)Se4 tetrahedra and corners with four equivalent Hg(2)Se4 tetrahedra. All Ge(1)-Se(1) bond lengths are 2.38 Å. Se(1) is bonded in a trigonal non-coplanar geometry to one Hg(1), one Hg(2), and one Ge(1) atom.