Rb5SiAs3 crystallizes in the orthorhombic Pnma space group. There are five inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to one As(1), two equivalent As(3), and three equivalent As(2) atoms. In the second Rb site, Rb(2) is bonded in a 7-coordinate geometry to two equivalent Si(1), one As(1), two equivalent As(2), and two equivalent As(3) atoms. In the third Rb site, Rb(3) is bonded in a 5-coordinate geometry to two equivalent As(1) and three equivalent As(2) atoms. In the fourth Rb site, Rb(4) is bonded to one As(2), one As(3), and two equivalent As(1) atoms to form distorted corner-sharing RbAs4 tetrahedra. In the fifth Rb site, Rb(5) is bonded in a 7-coordinate geometry to two equivalent Si(1), two equivalent As(3), and three equivalent As(1) atoms. Si(1) is bonded in a distorted trigonal planar geometry to two equivalent Rb(2), two equivalent Rb(5), one As(1), one As(2), and one As(3) atom. There are three inequivalent As sites. In the first As site, As(3) is bonded in a 1-coordinate geometry to one Rb(4), two equivalent Rb(1), two equivalent Rb(2), two equivalent Rb(5), and one Si(1) atom. In the second As site, As(1) is bonded in a 10-coordinate geometry to one Rb(1), one Rb(2), two equivalent Rb(3), two equivalent Rb(4), three equivalent Rb(5), and one Si(1) atom. In the third As site, As(2) is bonded in a 10-coordinate geometry to one Rb(4), two equivalent Rb(2), three equivalent Rb(1), three equivalent Rb(3), and one Si(1) atom.
Rb5SiAs3 crystallizes in the orthorhombic Pnma space group. There are five inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to one As(1), two equivalent As(3), and three equivalent As(2) atoms. The Rb(1)-As(1) bond length is 3.92 Å. Both Rb(1)-As(3) bond lengths are 3.97 Å. There are two shorter (3.69 Å) and one longer (3.88 Å) Rb(1)-As(2) bond length. In the second Rb site, Rb(2) is bonded in a 7-coordinate geometry to two equivalent Si(1), one As(1), two equivalent As(2), and two equivalent As(3) atoms. Both Rb(2)-Si(1) bond lengths are 3.62 Å. The Rb(2)-As(1) bond length is 3.50 Å. Both Rb(2)-As(2) bond lengths are 3.78 Å. Both Rb(2)-As(3) bond lengths are 3.53 Å. In the third Rb site, Rb(3) is bonded in a 5-coordinate geometry to two equivalent As(1) and three equivalent As(2) atoms. Both Rb(3)-As(1) bond lengths are 3.70 Å. There are two shorter (3.62 Å) and one longer (3.65 Å) Rb(3)-As(2) bond length. In the fourth Rb site, Rb(4) is bonded to one As(2), one As(3), and two equivalent As(1) atoms to form distorted corner-sharing RbAs4 tetrahedra. The Rb(4)-As(2) bond length is 3.48 Å. The Rb(4)-As(3) bond length is 3.56 Å. Both Rb(4)-As(1) bond lengths are 3.53 Å. In the fifth Rb site, Rb(5) is bonded in a 7-coordinate geometry to two equivalent Si(1), two equivalent As(3), and three equivalent As(1) atoms. Both Rb(5)-Si(1) bond lengths are 3.75 Å. Both Rb(5)-As(3) bond lengths are 3.65 Å. There is one shorter (3.63 Å) and two longer (3.79 Å) Rb(5)-As(1) bond lengths. Si(1) is bonded in a distorted trigonal planar geometry to two equivalent Rb(2), two equivalent Rb(5), one As(1), one As(2), and one As(3) atom. The Si(1)-As(1) bond length is 2.29 Å. The Si(1)-As(2) bond length is 2.29 Å. The Si(1)-As(3) bond length is 2.31 Å. There are three inequivalent As sites. In the first As site, As(3) is bonded in a 1-coordinate geometry to one Rb(4), two equivalent Rb(1), two equivalent Rb(2), two equivalent Rb(5), and one Si(1) atom. In the second As site, As(1) is bonded in a 10-coordinate geometry to one Rb(1), one Rb(2), two equivalent Rb(3), two equivalent Rb(4), three equivalent Rb(5), and one Si(1) atom. In the third As site, As(2) is bonded in a 10-coordinate geometry to one Rb(4), two equivalent Rb(2), three equivalent Rb(1), three equivalent Rb(3), and one Si(1) atom.