Materials Data on Sn2SI2 by Materials Project
Sn2SI2 crystallizes in the orthorhombic Pnma space group. The structure is one-dimensional and consists of six Sn2SI2 ribbons oriented in the (1, 0, 0) direction. In two of the Sn2SI2 ribbons, there are two inequivalent Sn2+ sites. In the first Sn2+ site, Sn2+ is bonded to one S2- and four I1- atoms to form distorted edge-sharing SnSI4 square pyramids. The Sn–S bond length is 2.62 Å. There are two shorter (3.14 Å) and two longer (3.35 Å) Sn–I bond lengths. In the second Sn2+ site, Sn2+ is bonded in a 5-coordinate geometry to three equivalent S2- and two equivalent I1- atoms. There are one shorter (2.65 Å) and two longer (2.79 Å) Sn–S bond lengths. Both Sn–I bond lengths are 3.45 Å. S2- is bonded to four Sn2+ atoms to form a mixture of distorted corner and edge-sharing SSn4 trigonal pyramids. There are two 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 an L-shaped geometry to two equivalent Sn2+ atoms. In four of the Sn2SI2 ribbons, there are four inequivalent Sn2+ sites. In the first Sn2+ site, Sn2+ is bonded to one S2- and four I1- atoms to form distorted edge-sharing SnSI4 square pyramids. The Sn–S bond length is 2.63 Å. There are two shorter (3.07 Å) and two longer (3.39 Å) Sn–I bond lengths. In the second Sn2+ site, Sn2+ is bonded in a 5-coordinate geometry to three S2- and two equivalent I1- atoms. There are one shorter (2.67 Å) and two longer (2.78 Å) Sn–S bond lengths. Both Sn–I bond lengths are 3.44 Å. In the third Sn2+ site, Sn2+ is bonded to one S2- and four I1- atoms to form distorted edge-sharing SnSI4 square pyramids. The Sn–S bond length is 2.62 Å. There are two shorter (3.11 Å) and two longer (3.38 Å) Sn–I bond lengths. In the fourth Sn2+ site, Sn2+ is bonded in a 5-coordinate geometry to three S2- and two equivalent I1- atoms. There are one shorter (2.62 Å) and two longer (2.80 Å) Sn–S bond lengths. Both Sn–I bond lengths are 3.45 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to four Sn2+ atoms to form a mixture of distorted corner and edge-sharing SSn4 trigonal pyramids. In the second S2- site, S2- is bonded to four Sn2+ atoms to form a mixture of distorted corner and edge-sharing SSn4 tetrahedra. There are four 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 an L-shaped geometry to two 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 4-coordinate geometry to four Sn2+ atoms.