Na2Ge2ZnSe6 crystallizes in the tetragonal I4/mcm space group. Na(1) is bonded in a distorted square co-planar geometry to four equivalent Se(2) atoms. Zn(1) is bonded to four equivalent Se(2) atoms to form distorted ZnSe4 tetrahedra that share edges with two equivalent Ge(1)Se4 tetrahedra. Ge(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form GeSe4 tetrahedra that share  an edgeedge with one Zn(1)Se4 tetrahedra and  an edgeedge with one Ge(1)Se4 tetrahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in an L-shaped geometry to two equivalent Ge(1) atoms. In the second Se site, Se(2) is bonded to two equivalent Na(1), one Zn(1), and one Ge(1) atom to form a mixture of corner and edge-sharing SeNa2ZnGe trigonal pyramids.
Na2Ge2ZnSe6 crystallizes in the tetragonal I4/mcm space group. Na(1) is bonded in a distorted square co-planar geometry to four equivalent Se(2) atoms. All Na(1)-Se(2) bond lengths are 3.08 Å. Zn(1) is bonded to four equivalent Se(2) atoms to form distorted ZnSe4 tetrahedra that share edges with two equivalent Ge(1)Se4 tetrahedra. All Zn(1)-Se(2) bond lengths are 2.52 Å. Ge(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form GeSe4 tetrahedra that share  an edgeedge with one Zn(1)Se4 tetrahedra and  an edgeedge with one Ge(1)Se4 tetrahedra. Both Ge(1)-Se(1) bond lengths are 2.44 Å. Both Ge(1)-Se(2) bond lengths are 2.37 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in an L-shaped geometry to two equivalent Ge(1) atoms. In the second Se site, Se(2) is bonded to two equivalent Na(1), one Zn(1), and one Ge(1) atom to form a mixture of corner and edge-sharing SeNa2ZnGe trigonal pyramids.