Dy3CuGeSe7 crystallizes in the hexagonal P6_3 space group. Dy(1) is bonded in a 9-coordinate geometry to one Cu(1), one Se(3), three equivalent Se(2), and four equivalent Se(1) atoms. Cu(1) is bonded in a trigonal planar geometry to three equivalent Dy(1) and three equivalent Se(1) atoms. Ge(1) is bonded in a tetrahedral geometry to one Se(3) and three equivalent Se(2) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to four equivalent Dy(1) and one Cu(1) atom. In the second Se site, Se(2) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Dy(1) and one Ge(1) atom. In the third Se site, Se(3) is bonded in a tetrahedral geometry to three equivalent Dy(1) and one Ge(1) atom.
Dy3CuGeSe7 crystallizes in the hexagonal P6_3 space group. Dy(1) is bonded in a 9-coordinate geometry to one Cu(1), one Se(3), three equivalent Se(2), and four equivalent Se(1) atoms. The Dy(1)-Cu(1) bond length is 3.23 Å. The Dy(1)-Se(3) bond length is 3.06 Å. There are a spread of Dy(1)-Se(2) bond distances ranging from 2.94-3.18 Å. There are a spread of Dy(1)-Se(1) bond distances ranging from 2.87-3.37 Å. Cu(1) is bonded in a trigonal planar geometry to three equivalent Dy(1) and three equivalent Se(1) atoms. All Cu(1)-Se(1) bond lengths are 2.37 Å. Ge(1) is bonded in a tetrahedral geometry to one Se(3) and three equivalent Se(2) atoms. The Ge(1)-Se(3) bond length is 2.36 Å. All Ge(1)-Se(2) bond lengths are 2.40 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to four equivalent Dy(1) and one Cu(1) atom. In the second Se site, Se(2) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Dy(1) and one Ge(1) atom. In the third Se site, Se(3) is bonded in a tetrahedral geometry to three equivalent Dy(1) and one Ge(1) atom.