LaCrSe3 crystallizes in the orthorhombic Pnma space group. La(1) is bonded in a 9-coordinate geometry to two equivalent Se(3), three equivalent Se(2), and four equivalent Se(1) atoms. Cr(1) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(3) atoms to form edge-sharing CrSe6 octahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to four equivalent La(1) and one Cr(1) atom to form distorted SeLa4Cr square pyramids that share corners with four equivalent Se(1)La4Cr square pyramids, corners with three equivalent Se(3)La2Cr3 trigonal bipyramids, edges with four equivalent Se(1)La4Cr square pyramids, and edges with four equivalent Se(3)La2Cr3 trigonal bipyramids. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to three equivalent La(1) and two equivalent Cr(1) atoms. In the third Se site, Se(3) is bonded to two equivalent La(1) and three equivalent Cr(1) atoms to form distorted SeLa2Cr3 trigonal bipyramids that share corners with three equivalent Se(1)La4Cr square pyramids, corners with four equivalent Se(3)La2Cr3 trigonal bipyramids, edges with four equivalent Se(1)La4Cr square pyramids, and edges with two equivalent Se(3)La2Cr3 trigonal bipyramids.
LaCrSe3 crystallizes in the orthorhombic Pnma space group. La(1) is bonded in a 9-coordinate geometry to two equivalent Se(3), three equivalent Se(2), and four equivalent Se(1) atoms. There is one shorter (3.19 Å) and one longer (3.37 Å) La(1)-Se(3) bond length. There are two shorter (3.10 Å) and one longer (3.21 Å) La(1)-Se(2) bond length. There are two shorter (3.12 Å) and two longer (3.13 Å) La(1)-Se(1) bond lengths. Cr(1) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(3) atoms to form edge-sharing CrSe6 octahedra. The Cr(1)-Se(1) bond length is 2.52 Å. Both Cr(1)-Se(2) bond lengths are 2.61 Å. There is one shorter (2.51 Å) and two longer (2.57 Å) Cr(1)-Se(3) bond lengths. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to four equivalent La(1) and one Cr(1) atom to form distorted SeLa4Cr square pyramids that share corners with four equivalent Se(1)La4Cr square pyramids, corners with three equivalent Se(3)La2Cr3 trigonal bipyramids, edges with four equivalent Se(1)La4Cr square pyramids, and edges with four equivalent Se(3)La2Cr3 trigonal bipyramids. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to three equivalent La(1) and two equivalent Cr(1) atoms. In the third Se site, Se(3) is bonded to two equivalent La(1) and three equivalent Cr(1) atoms to form distorted SeLa2Cr3 trigonal bipyramids that share corners with three equivalent Se(1)La4Cr square pyramids, corners with four equivalent Se(3)La2Cr3 trigonal bipyramids, edges with four equivalent Se(1)La4Cr square pyramids, and edges with two equivalent Se(3)La2Cr3 trigonal bipyramids.