Tb3CuGeSe7 crystallizes in the hexagonal P6_3 space group. Tb(1) is bonded in a 9-coordinate geometry to one Cu(1), one Se(2), three equivalent Se(3), and four equivalent Se(1) atoms. Cu(1) is bonded in a trigonal planar geometry to three equivalent Tb(1) and three equivalent Se(1) atoms. Ge(1) is bonded in a tetrahedral geometry to one Se(2) and three equivalent Se(3) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to four equivalent Tb(1) and one Cu(1) atom. In the second Se site, Se(2) is bonded in a tetrahedral geometry to three equivalent Tb(1) and one Ge(1) atom. In the third Se site, Se(3) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Tb(1) and one Ge(1) atom.
Tb3CuGeSe7 crystallizes in the hexagonal P6_3 space group. Tb(1) is bonded in a 9-coordinate geometry to one Cu(1), one Se(2), three equivalent Se(3), and four equivalent Se(1) atoms. The Tb(1)-Cu(1) bond length is 3.24 Å. The Tb(1)-Se(2) bond length is 3.07 Å. There are a spread of Tb(1)-Se(3) bond distances ranging from 2.95-3.18 Å. There are a spread of Tb(1)-Se(1) bond distances ranging from 2.88-3.35 Å. Cu(1) is bonded in a trigonal planar geometry to three equivalent Tb(1) and three equivalent Se(1) atoms. All Cu(1)-Se(1) bond lengths are 2.38 Å. Ge(1) is bonded in a tetrahedral geometry to one Se(2) and three equivalent Se(3) atoms. The Ge(1)-Se(2) bond length is 2.36 Å. All Ge(1)-Se(3) 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 Tb(1) and one Cu(1) atom. In the second Se site, Se(2) is bonded in a tetrahedral geometry to three equivalent Tb(1) and one Ge(1) atom. In the third Se site, Se(3) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Tb(1) and one Ge(1) atom.