Materials Data on Sn4SI6 by Materials Project
Sn4SI6 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of two Sn4SI6 sheets oriented in the (-1, 0, 1) direction. there are four inequivalent Sn2+ sites. In the first Sn2+ site, Sn2+ is bonded to one S2- and four I1- atoms to form distorted SnSI4 square pyramids that share corners with two equivalent SnI6 octahedra and edges with two equivalent SnSI4 square pyramids. The corner-sharing octahedral tilt angles are 63°. The Sn–S bond length is 2.66 Å. There are two shorter (3.18 Å) and two longer (3.32 Å) Sn–I bond lengths. In the second Sn2+ site, Sn2+ is bonded to five I1- atoms to form SnI5 square pyramids that share corners with two equivalent SnI6 octahedra and edges with four equivalent SnI5 square pyramids. The corner-sharing octahedral tilt angles are 65°. There are a spread of Sn–I bond distances ranging from 3.07–3.25 Å. In the third Sn2+ site, Sn2+ is bonded in a 5-coordinate geometry to three equivalent S2- and two equivalent I1- atoms. There are one shorter (2.64 Å) and two longer (2.78 Å) Sn–S bond lengths. Both Sn–I bond lengths are 3.52 Å. In the fourth Sn2+ site, Sn2+ is bonded to six I1- atoms to form SnI6 octahedra that share corners with four SnSI4 square pyramids and edges with two equivalent SnI6 octahedra. There are a spread of Sn–I bond distances ranging from 3.16–3.32 Å. S2- is bonded to four Sn2+ atoms to form a mixture of distorted edge and corner-sharing SSn4 tetrahedra. There are six inequivalent I1- sites. In the first I1- site, I1- is bonded in a 4-coordinate geometry to four Sn2+ atoms. In the second I1- site, I1- is bonded in a 3-coordinate geometry to three equivalent Sn2+ atoms. In the third I1- site, I1- is bonded in an L-shaped geometry to two equivalent Sn2+ atoms. In the fourth I1- site, I1- is bonded in a trigonal non-coplanar geometry to three Sn2+ atoms. In the fifth I1- site, I1- is bonded in an L-shaped geometry to two equivalent Sn2+ atoms. In the sixth I1- site, I1- is bonded in a distorted trigonal non-coplanar geometry to three Sn2+ atoms.