Dy3NiGaSe7 crystallizes in the hexagonal P6_3 space group. Dy(1) is bonded in a 7-coordinate geometry to one Se(2), three equivalent Se(1), and three equivalent Se(3) atoms. Ni(1) is bonded to six equivalent Se(3) atoms to form face-sharing NiSe6 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 Dy(1) and one Ga(1) atom. In the second Se site, Se(2) is bonded to three equivalent Dy(1) and one Ga(1) atom to form corner-sharing SeDy3Ga tetrahedra. In the third Se site, Se(3) is bonded to three equivalent Dy(1) and two equivalent Ni(1) atoms to form SeDy3Ni2 square pyramids that share corners with two equivalent Se(3)Dy3Ni2 square pyramids, corners with three equivalent Se(2)Dy3Ga tetrahedra, edges with four equivalent Se(3)Dy3Ni2 square pyramids, and faces with two equivalent Se(3)Dy3Ni2 square pyramids.
Dy3NiGaSe7 crystallizes in the hexagonal P6_3 space group. Dy(1) is bonded in a 7-coordinate geometry to one Se(2), three equivalent Se(1), and three equivalent Se(3) atoms. The Dy(1)-Se(2) bond length is 2.87 Å. There are a spread of Dy(1)-Se(1) bond distances ranging from 2.93-3.17 Å. There are a spread of Dy(1)-Se(3) bond distances ranging from 2.86-2.94 Å. Ni(1) is bonded to six equivalent Se(3) atoms to form face-sharing NiSe6 octahedra. There are three shorter (2.54 Å) and three longer (2.67 Å) Ni(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 2.41 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 Dy(1) and one Ga(1) atom. In the second Se site, Se(2) is bonded to three equivalent Dy(1) and one Ga(1) atom to form corner-sharing SeDy3Ga tetrahedra. In the third Se site, Se(3) is bonded to three equivalent Dy(1) and two equivalent Ni(1) atoms to form SeDy3Ni2 square pyramids that share corners with two equivalent Se(3)Dy3Ni2 square pyramids, corners with three equivalent Se(2)Dy3Ga tetrahedra, edges with four equivalent Se(3)Dy3Ni2 square pyramids, and faces with two equivalent Se(3)Dy3Ni2 square pyramids.