Materials Data on Si18Sn by Materials Project

Sn(Si)18 crystallizes in the triclinic P1 space group. The structure is one-dimensional and consists of six Si ribbons oriented in the (1, 0, 0) direction and one Sn ribbon oriented in the (1, 0, 0) direction. In each Si ribbon, there are three inequivalent Si sites. In the first Si site, Si is bonded in a 2-coordinate geometry to two equivalent Si atoms. Both Si–Si bond lengths are 2.42 Å. In the second Si site, Si is bonded in a 4-coordinate geometry to two equivalent Si atoms. Both Si–Si bond lengths are 2.41 Å. In the third Si site, Si is bonded in a square co-planar geometry to four Si atoms. In the Sn ribbon, Sn is bonded in a distorted linear geometry to two equivalent Sn atoms. Both Sn–Sn bond lengths are 3.53 Å.