La3CuSnSe7 crystallizes in the hexagonal P6_3 space group. La(1) is bonded in a 8-coordinate geometry to 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 Se(1) atoms. Sn(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 La(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 La(1) and one Sn(1) atom. In the third Se site, Se(3) is bonded in a tetrahedral geometry to three equivalent La(1) and one Sn(1) atom.
La3CuSnSe7 crystallizes in the hexagonal P6_3 space group. La(1) is bonded in a 8-coordinate geometry to one Se(3), three equivalent Se(2), and four equivalent Se(1) atoms. The La(1)-Se(3) bond length is 3.17 Å. There are a spread of La(1)-Se(2) bond distances ranging from 3.08-3.27 Å. There are a spread of La(1)-Se(1) bond distances ranging from 2.97-3.47 Å. Cu(1) is bonded in a trigonal planar geometry to three equivalent Se(1) atoms. All Cu(1)-Se(1) bond lengths are 2.37 Å. Sn(1) is bonded in a tetrahedral geometry to one Se(3) and three equivalent Se(2) atoms. The Sn(1)-Se(3) bond length is 2.49 Å. All Sn(1)-Se(2) bond lengths are 2.54 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to four equivalent La(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 La(1) and one Sn(1) atom. In the third Se site, Se(3) is bonded in a tetrahedral geometry to three equivalent La(1) and one Sn(1) atom.