SrCuLaSe3 crystallizes in the orthorhombic Pnma space group. Sr(1) is bonded in a 7-coordinate geometry to one Se(1), three equivalent Se(2), and three equivalent Se(3) atoms. La(1) is bonded in a 7-coordinate geometry to one Se(2), two equivalent Se(3), and four equivalent Se(1) atoms. Cu(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form corner-sharing CuSe4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Sr(1), four equivalent La(1), and one Cu(1) atom to form distorted SeSrLa4Cu octahedra that share corners with four equivalent Se(1)SrLa4Cu octahedra, corners with six equivalent Se(3)Sr3La2Cu octahedra, edges with four equivalent Se(1)SrLa4Cu octahedra, and faces with two equivalent Se(3)Sr3La2Cu octahedra. The corner-sharing octahedral tilt angles range from 24-59°. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Sr(1), one La(1), and two equivalent Cu(1) atoms. In the third Se site, Se(3) is bonded to three equivalent Sr(1), two equivalent La(1), and one Cu(1) atom to form distorted SeSr3La2Cu octahedra that share corners with six equivalent Se(1)SrLa4Cu octahedra, edges with four equivalent Se(3)Sr3La2Cu octahedra, and faces with two equivalent Se(1)SrLa4Cu octahedra. The corner-sharing octahedral tilt angles range from 46-59°.
SrCuLaSe3 crystallizes in the orthorhombic Pnma space group. Sr(1) is bonded in a 7-coordinate geometry to one Se(1), three equivalent Se(2), and three equivalent Se(3) atoms. The Sr(1)-Se(1) bond length is 3.23 Å. There are two shorter (3.10 Å) and one longer (3.24 Å) Sr(1)-Se(2) bond length. There are two shorter (3.11 Å) and one longer (3.32 Å) Sr(1)-Se(3) bond length. La(1) is bonded in a 7-coordinate geometry to one Se(2), two equivalent Se(3), and four equivalent Se(1) atoms. The La(1)-Se(2) bond length is 3.12 Å. Both La(1)-Se(3) bond lengths are 3.10 Å. There are two shorter (3.08 Å) and two longer (3.15 Å) La(1)-Se(1) bond lengths. Cu(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form corner-sharing CuSe4 tetrahedra. The Cu(1)-Se(1) bond length is 2.50 Å. The Cu(1)-Se(3) bond length is 2.46 Å. Both Cu(1)-Se(2) bond lengths are 2.45 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Sr(1), four equivalent La(1), and one Cu(1) atom to form distorted SeSrLa4Cu octahedra that share corners with four equivalent Se(1)SrLa4Cu octahedra, corners with six equivalent Se(3)Sr3La2Cu octahedra, edges with four equivalent Se(1)SrLa4Cu octahedra, and faces with two equivalent Se(3)Sr3La2Cu octahedra. The corner-sharing octahedral tilt angles range from 24-59°. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Sr(1), one La(1), and two equivalent Cu(1) atoms. In the third Se site, Se(3) is bonded to three equivalent Sr(1), two equivalent La(1), and one Cu(1) atom to form distorted SeSr3La2Cu octahedra that share corners with six equivalent Se(1)SrLa4Cu octahedra, edges with four equivalent Se(3)Sr3La2Cu octahedra, and faces with two equivalent Se(1)SrLa4Cu octahedra. The corner-sharing octahedral tilt angles range from 46-59°.