Rb3AsSe16 crystallizes in the cubic Fd-3 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a q6 geometry to twelve equivalent Se(1) atoms. In the second Rb site, Rb(2) is bonded in a 14-coordinate geometry to two equivalent As(1), six equivalent Se(1), and six equivalent Se(2) atoms. As(1) is bonded to four equivalent Rb(2) and four equivalent Se(2) atoms to form AsRb4Se4 tetrahedra that share corners with four equivalent As(1)Rb4Se4 tetrahedra and corners with twenty-four equivalent Se(1)Rb2Se2 tetrahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to one Rb(1), one Rb(2), and two equivalent Se(1) atoms to form distorted SeRb2Se2 tetrahedra that share corners with two equivalent As(1)Rb4Se4 tetrahedra, corners with fourteen equivalent Se(1)Rb2Se2 tetrahedra, and edges with two equivalent Se(1)Rb2Se2 tetrahedra. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to three equivalent Rb(2) and one As(1) atom.
Rb3AsSe16 crystallizes in the cubic Fd-3 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a q6 geometry to twelve equivalent Se(1) atoms. All Rb(1)-Se(1) bond lengths are 3.83 Å. In the second Rb site, Rb(2) is bonded in a 14-coordinate geometry to two equivalent As(1), six equivalent Se(1), and six equivalent Se(2) atoms. Both Rb(2)-As(1) bond lengths are 3.67 Å. All Rb(2)-Se(1) bond lengths are 3.87 Å. All Rb(2)-Se(2) bond lengths are 3.63 Å. As(1) is bonded to four equivalent Rb(2) and four equivalent Se(2) atoms to form AsRb4Se4 tetrahedra that share corners with four equivalent As(1)Rb4Se4 tetrahedra and corners with twenty-four equivalent Se(1)Rb2Se2 tetrahedra. All As(1)-Se(2) bond lengths are 2.33 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to one Rb(1), one Rb(2), and two equivalent Se(1) atoms to form distorted SeRb2Se2 tetrahedra that share corners with two equivalent As(1)Rb4Se4 tetrahedra, corners with fourteen equivalent Se(1)Rb2Se2 tetrahedra, and edges with two equivalent Se(1)Rb2Se2 tetrahedra. Both Se(1)-Se(1) bond lengths are 2.39 Å. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to three equivalent Rb(2) and one As(1) atom.