Materials Data on Na5Sn2 by Materials Project
Na5Sn2 crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three Na5Sn2 sheets oriented in the (0, 0, 1) direction. there are three inequivalent Na sites. In the first Na site, Na is bonded in a body-centered cubic geometry to eight Na atoms. There are six shorter (3.33 Å) and two longer (3.35 Å) Na–Na bond lengths. In the second Na site, Na is bonded in a distorted trigonal non-coplanar geometry to one Na and three equivalent Sn atoms. All Na–Sn bond lengths are 3.34 Å. In the third Na site, Na is bonded to three equivalent Na and four equivalent Sn atoms to form a mixture of distorted corner, edge, and face-sharing NaNa3Sn4 tetrahedra. There are one shorter (3.33 Å) and three longer (3.39 Å) Na–Sn bond lengths. Sn is bonded in a 8-coordinate geometry to seven Na atoms.