Sm3CoGaSe7 crystallizes in the hexagonal P6_3 space group. Sm(1) is bonded in a 7-coordinate geometry to one Se(2), three equivalent Se(1), and three equivalent Se(3) atoms. Co(1) is bonded to six equivalent Se(3) atoms to form face-sharing CoSe6 octahedra. Ga(1) is bonded in a tetrahedral geometry to one Se(2) and three equivalent Se(1) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Sm(1) and one Ga(1) atom. In the second Se site, Se(2) is bonded to three equivalent Sm(1) and one Ga(1) atom to form corner-sharing SeSm3Ga tetrahedra. In the third Se site, Se(3) is bonded to three equivalent Sm(1) and two equivalent Co(1) atoms to form distorted SeSm3Co2 square pyramids that share corners with two equivalent Se(3)Sm3Co2 square pyramids, corners with three equivalent Se(2)Sm3Ga tetrahedra, edges with four equivalent Se(3)Sm3Co2 square pyramids, and faces with two equivalent Se(3)Sm3Co2 square pyramids.
Sm3CoGaSe7 crystallizes in the hexagonal P6_3 space group. Sm(1) is bonded in a 7-coordinate geometry to one Se(2), three equivalent Se(1), and three equivalent Se(3) atoms. The Sm(1)-Se(2) bond length is 2.93 Å. There are a spread of Sm(1)-Se(1) bond distances ranging from 2.98-3.19 Å. There are a spread of Sm(1)-Se(3) bond distances ranging from 2.91-3.01 Å. Co(1) is bonded to six equivalent Se(3) atoms to form face-sharing CoSe6 octahedra. There are three shorter (2.53 Å) and three longer (2.58 Å) Co(1)-Se(3) bond lengths. Ga(1) is bonded in a tetrahedral geometry to one Se(2) and three equivalent Se(1) atoms. The Ga(1)-Se(2) bond length is 2.40 Å. All Ga(1)-Se(1) bond lengths are 2.42 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Sm(1) and one Ga(1) atom. In the second Se site, Se(2) is bonded to three equivalent Sm(1) and one Ga(1) atom to form corner-sharing SeSm3Ga tetrahedra. In the third Se site, Se(3) is bonded to three equivalent Sm(1) and two equivalent Co(1) atoms to form distorted SeSm3Co2 square pyramids that share corners with two equivalent Se(3)Sm3Co2 square pyramids, corners with three equivalent Se(2)Sm3Ga tetrahedra, edges with four equivalent Se(3)Sm3Co2 square pyramids, and faces with two equivalent Se(3)Sm3Co2 square pyramids.