Materials Data on RbNa2Si17 by Materials Project
RbNa2Si17 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Rb is bonded in a 12-coordinate geometry to twenty-eight Si atoms. There are twelve shorter (3.96 Å) and sixteen longer (4.04 Å) Rb–Si bond lengths. Na is bonded in a 8-coordinate geometry to twenty Si atoms. There are a spread of Na–Si bond distances ranging from 3.21–3.39 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded in a 7-coordinate geometry to one Rb, three equivalent Na, and four Si atoms. There are one shorter (2.37 Å) and three longer (2.38 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a body-centered cubic geometry to four equivalent Na and four equivalent Si atoms. In the third Si site, Si is bonded in a 4-coordinate geometry to two equivalent Rb, two equivalent Na, and four Si atoms. There are two shorter (2.39 Å) and one longer (2.40 Å) Si–Si bond lengths.