Cr4(Ga2Se5)3 crystallizes in the monoclinic Cm space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(1), one Se(4), two equivalent Se(3), and two equivalent Se(8) atoms to form CrSe6 octahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, and edges with six equivalent Cr(2)Se6 octahedra. In the second Cr site, Cr(2) is bonded to one Se(1), one Se(4), two equivalent Se(3), and two equivalent Se(8) atoms to form CrSe6 octahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, edges with three equivalent Cr(1)Se6 octahedra, and edges with three equivalent Cr(2)Se6 octahedra. In the third Cr site, Cr(3) is bonded to one Se(10), one Se(7), two equivalent Se(2), and two equivalent Se(6) atoms to form CrSe6 octahedra that share corners with two equivalent Ga(2)Se4 tetrahedra, corners with two equivalent Ga(3)Se4 tetrahedra, edges with two equivalent Ga(2)Se4 tetrahedra, and edges with two equivalent Ga(3)Se4 tetrahedra. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one Se(3), one Se(5), and two equivalent Se(9) atoms to form GaSe4 tetrahedra that share  a cornercorner with one Cr(1)Se6 octahedra, corners with two equivalent Cr(2)Se6 octahedra, corners with two equivalent Ga(3)Se4 tetrahedra, and corners with three equivalent Ga(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-62°. In the second Ga site, Ga(2) is bonded to one Se(7), one Se(8), and two equivalent Se(2) atoms to form GaSe4 tetrahedra that share  a cornercorner with one Cr(1)Se6 octahedra,  a cornercorner with one Cr(3)Se6 octahedra, corners with two equivalent Cr(2)Se6 octahedra, corners with three equivalent Ga(2)Se4 tetrahedra, and  an edgeedge with one Cr(3)Se6 octahedra. The corner-sharing octahedral tilt angles range from 20-61°. In the third Ga site, Ga(3) is bonded to one Se(10), one Se(9), and two equivalent Se(6) atoms to form GaSe4 tetrahedra that share  a cornercorner with one Cr(3)Se6 octahedra, corners with two equivalent Ga(1)Se4 tetrahedra, corners with three equivalent Ga(3)Se4 tetrahedra, and  an edgeedge with one Cr(3)Se6 octahedra. The corner-sharing octahedral tilt angles are 20°. There are ten inequivalent Se sites. In the first Se site, Se(10) is bonded in a distorted T-shaped geometry to one Cr(3) and two equivalent Ga(3) atoms. In the second Se site, Se(1) is bonded in a distorted T-shaped geometry to one Cr(1) and two equivalent Cr(2) atoms. In the third Se site, Se(2) is bonded in a distorted T-shaped geometry to one Cr(3) and two equivalent Ga(2) atoms. In the fourth Se site, Se(3) is bonded to one Cr(1), two equivalent Cr(2), and one Ga(1) atom to form a mixture of distorted edge and corner-sharing SeCr3Ga tetrahedra. In the fifth Se site, Se(4) is bonded in a distorted T-shaped geometry to one Cr(1) and two equivalent Cr(2) atoms. In the sixth Se site, Se(5) is bonded in a water-like geometry to two equivalent Ga(1) atoms. In the seventh Se site, Se(6) is bonded in a distorted T-shaped geometry to one Cr(3) and two equivalent Ga(3) atoms. In the eighth Se site, Se(7) is bonded in a distorted T-shaped geometry to one Cr(3) and two equivalent Ga(2) atoms. In the ninth Se site, Se(8) is bonded to one Cr(1), two equivalent Cr(2), and one Ga(2) atom to form a mixture of distorted edge and corner-sharing SeCr3Ga tetrahedra. In the tenth Se site, Se(9) is bonded in a trigonal non-coplanar geometry to one Ga(3) and two equivalent Ga(1) atoms.
Cr4(Ga2Se5)3 crystallizes in the monoclinic Cm space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(1), one Se(4), two equivalent Se(3), and two equivalent Se(8) atoms to form CrSe6 octahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, and edges with six equivalent Cr(2)Se6 octahedra. The Cr(1)-Se(1) bond length is 2.58 Å. The Cr(1)-Se(4) bond length is 2.57 Å. Both Cr(1)-Se(3) bond lengths are 2.57 Å. Both Cr(1)-Se(8) bond lengths are 2.57 Å. In the second Cr site, Cr(2) is bonded to one Se(1), one Se(4), two equivalent Se(3), and two equivalent Se(8) atoms to form CrSe6 octahedra that share corners with two equivalent Ga(1)Se4 tetrahedra, corners with two equivalent Ga(2)Se4 tetrahedra, edges with three equivalent Cr(1)Se6 octahedra, and edges with three equivalent Cr(2)Se6 octahedra. The Cr(2)-Se(1) bond length is 2.49 Å. The Cr(2)-Se(4) bond length is 2.48 Å. There is one shorter (2.59 Å) and one longer (2.61 Å) Cr(2)-Se(3) bond length. There is one shorter (2.58 Å) and one longer (2.62 Å) Cr(2)-Se(8) bond length. In the third Cr site, Cr(3) is bonded to one Se(10), one Se(7), two equivalent Se(2), and two equivalent Se(6) atoms to form CrSe6 octahedra that share corners with two equivalent Ga(2)Se4 tetrahedra, corners with two equivalent Ga(3)Se4 tetrahedra, edges with two equivalent Ga(2)Se4 tetrahedra, and edges with two equivalent Ga(3)Se4 tetrahedra. The Cr(3)-Se(10) bond length is 2.60 Å. The Cr(3)-Se(7) bond length is 2.61 Å. Both Cr(3)-Se(2) bond lengths are 2.66 Å. Both Cr(3)-Se(6) bond lengths are 2.66 Å. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one Se(3), one Se(5), and two equivalent Se(9) atoms to form GaSe4 tetrahedra that share  a cornercorner with one Cr(1)Se6 octahedra, corners with two equivalent Cr(2)Se6 octahedra, corners with two equivalent Ga(3)Se4 tetrahedra, and corners with three equivalent Ga(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 58-62°. The Ga(1)-Se(3) bond length is 2.47 Å. The Ga(1)-Se(5) bond length is 2.34 Å. There is one shorter (2.46 Å) and one longer (2.47 Å) Ga(1)-Se(9) bond length. In the second Ga site, Ga(2) is bonded to one Se(7), one Se(8), and two equivalent Se(2) atoms to form GaSe4 tetrahedra that share  a cornercorner with one Cr(1)Se6 octahedra,  a cornercorner with one Cr(3)Se6 octahedra, corners with two equivalent Cr(2)Se6 octahedra, corners with three equivalent Ga(2)Se4 tetrahedra, and  an edgeedge with one Cr(3)Se6 octahedra. The corner-sharing octahedral tilt angles range from 20-61°. The Ga(2)-Se(7) bond length is 2.42 Å. The Ga(2)-Se(8) bond length is 2.49 Å. There is one shorter (2.39 Å) and one longer (2.46 Å) Ga(2)-Se(2) bond length. In the third Ga site, Ga(3) is bonded to one Se(10), one Se(9), and two equivalent Se(6) atoms to form GaSe4 tetrahedra that share  a cornercorner with one Cr(3)Se6 octahedra, corners with two equivalent Ga(1)Se4 tetrahedra, corners with three equivalent Ga(3)Se4 tetrahedra, and  an edgeedge with one Cr(3)Se6 octahedra. The corner-sharing octahedral tilt angles are 20°. The Ga(3)-Se(10) bond length is 2.42 Å. The Ga(3)-Se(9) bond length is 2.49 Å. There is one shorter (2.39 Å) and one longer (2.45 Å) Ga(3)-Se(6) bond length. There are ten inequivalent Se sites. In the first Se site, Se(10) is bonded in a distorted T-shaped geometry to one Cr(3) and two equivalent Ga(3) atoms. In the second Se site, Se(1) is bonded in a distorted T-shaped geometry to one Cr(1) and two equivalent Cr(2) atoms. In the third Se site, Se(2) is bonded in a distorted T-shaped geometry to one Cr(3) and two equivalent Ga(2) atoms. In the fourth Se site, Se(3) is bonded to one Cr(1), two equivalent Cr(2), and one Ga(1) atom to form a mixture of distorted edge and corner-sharing SeCr3Ga tetrahedra. In the fifth Se site, Se(4) is bonded in a distorted T-shaped geometry to one Cr(1) and two equivalent Cr(2) atoms. In the sixth Se site, Se(5) is bonded in a water-like geometry to two equivalent Ga(1) atoms. In the seventh Se site, Se(6) is bonded in a distorted T-shaped geometry to one Cr(3) and two equivalent Ga(3) atoms. In the eighth Se site, Se(7) is bonded in a distorted T-shaped geometry to one Cr(3) and two equivalent Ga(2) atoms. In the ninth Se site, Se(8) is bonded to one Cr(1), two equivalent Cr(2), and one Ga(2) atom to form a mixture of distorted edge and corner-sharing SeCr3Ga tetrahedra. In the tenth Se site, Se(9) is bonded in a trigonal non-coplanar geometry to one Ga(3) and two equivalent Ga(1) atoms.