RbNa2Si17 crystallizes in the cubic Fd-3m space group. Rb(1) is bonded in a 12-coordinate geometry to four equivalent Si(2) and twenty-four equivalent Si(1) atoms. Na(1) is bonded in a 20-coordinate geometry to two equivalent Si(3), six equivalent Si(2), and twelve equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(2) is bonded in a 7-coordinate geometry to one Rb(1), three equivalent Na(1), one Si(3), and three equivalent Si(1) atoms. In the second Si site, Si(3) is bonded in a body-centered cubic geometry to four equivalent Na(1) and four equivalent Si(2) atoms. In the third Si site, Si(1) is bonded in a 4-coordinate geometry to two equivalent Rb(1), two equivalent Na(1), one Si(2), and three equivalent Si(1) atoms.
RbNa2Si17 crystallizes in the cubic Fd-3m space group. Rb(1) is bonded in a 12-coordinate geometry to four equivalent Si(2) and twenty-four equivalent Si(1) atoms. All Rb(1)-Si(2) bond lengths are 4.04 Å. There are twelve shorter (3.96 Å) and twelve longer (4.04 Å) Rb(1)-Si(1) bond lengths. Na(1) is bonded in a 20-coordinate geometry to two equivalent Si(3), six equivalent Si(2), and twelve equivalent Si(1) atoms. Both Na(1)-Si(3) bond lengths are 3.21 Å. All Na(1)-Si(2) bond lengths are 3.29 Å. All Na(1)-Si(1) bond lengths are 3.39 Å. There are three inequivalent Si sites. In the first Si site, Si(2) is bonded in a 7-coordinate geometry to one Rb(1), three equivalent Na(1), one Si(3), and three equivalent Si(1) atoms. The Si(2)-Si(3) bond length is 2.37 Å. All Si(2)-Si(1) bond lengths are 2.38 Å. In the second Si site, Si(3) is bonded in a body-centered cubic geometry to four equivalent Na(1) and four equivalent Si(2) atoms. In the third Si site, Si(1) is bonded in a 4-coordinate geometry to two equivalent Rb(1), two equivalent Na(1), one Si(2), and three equivalent Si(1) atoms. There are two shorter (2.39 Å) and one longer (2.40 Å) Si(1)-Si(1) bond length.