La3Cu2S7 crystallizes in the hexagonal P6_3 space group. La(1) is bonded in a 8-coordinate geometry to one S(2), three equivalent S(3), and four equivalent S(1) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a tetrahedral geometry to one S(2) and three equivalent S(3) atoms. In the second Cu site, Cu(2) is bonded in a trigonal planar geometry to three equivalent S(1) atoms. There are three inequivalent S sites. In the first S site, S(1) is bonded to four equivalent La(1) and one Cu(2) atom to form distorted SLa4Cu trigonal bipyramids that share corners with four equivalent S(2)La3Cu tetrahedra, corners with two equivalent S(1)La4Cu trigonal bipyramids, corners with eight equivalent S(3)La3Cu trigonal pyramids, edges with six equivalent S(1)La4Cu trigonal bipyramids, and edges with two equivalent S(3)La3Cu trigonal pyramids. In the second S site, S(2) is bonded to three equivalent La(1) and one Cu(1) atom to form SLa3Cu tetrahedra that share corners with twelve equivalent S(1)La4Cu trigonal bipyramids, corners with six equivalent S(3)La3Cu trigonal pyramids, and edges with three equivalent S(3)La3Cu trigonal pyramids. In the third S site, S(3) is bonded to three equivalent La(1) and one Cu(1) atom to form distorted SLa3Cu trigonal pyramids that share corners with two equivalent S(2)La3Cu tetrahedra, corners with eight equivalent S(1)La4Cu trigonal bipyramids, corners with four equivalent S(3)La3Cu trigonal pyramids,  an edgeedge with one S(2)La3Cu tetrahedra, edges with two equivalent S(1)La4Cu trigonal bipyramids, and edges with two equivalent S(3)La3Cu trigonal pyramids.
La3Cu2S7 crystallizes in the hexagonal P6_3 space group. La(1) is bonded in a 8-coordinate geometry to one S(2), three equivalent S(3), and four equivalent S(1) atoms. The La(1)-S(2) bond length is 2.99 Å. There are a spread of La(1)-S(3) bond distances ranging from 2.90-3.01 Å. There are a spread of La(1)-S(1) bond distances ranging from 2.94-3.12 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a tetrahedral geometry to one S(2) and three equivalent S(3) atoms. The Cu(1)-S(2) bond length is 2.22 Å. All Cu(1)-S(3) bond lengths are 2.26 Å. In the second Cu site, Cu(2) is bonded in a trigonal planar geometry to three equivalent S(1) atoms. All Cu(2)-S(1) bond lengths are 2.25 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded to four equivalent La(1) and one Cu(2) atom to form distorted SLa4Cu trigonal bipyramids that share corners with four equivalent S(2)La3Cu tetrahedra, corners with two equivalent S(1)La4Cu trigonal bipyramids, corners with eight equivalent S(3)La3Cu trigonal pyramids, edges with six equivalent S(1)La4Cu trigonal bipyramids, and edges with two equivalent S(3)La3Cu trigonal pyramids. In the second S site, S(2) is bonded to three equivalent La(1) and one Cu(1) atom to form SLa3Cu tetrahedra that share corners with twelve equivalent S(1)La4Cu trigonal bipyramids, corners with six equivalent S(3)La3Cu trigonal pyramids, and edges with three equivalent S(3)La3Cu trigonal pyramids. In the third S site, S(3) is bonded to three equivalent La(1) and one Cu(1) atom to form distorted SLa3Cu trigonal pyramids that share corners with two equivalent S(2)La3Cu tetrahedra, corners with eight equivalent S(1)La4Cu trigonal bipyramids, corners with four equivalent S(3)La3Cu trigonal pyramids,  an edgeedge with one S(2)La3Cu tetrahedra, edges with two equivalent S(1)La4Cu trigonal bipyramids, and edges with two equivalent S(3)La3Cu trigonal pyramids.