Materials Data on SmSI by Materials Project
SmSI is Cotunnite-derived structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three SmSI sheets oriented in the (0, 0, 1) direction. Sm3+ is bonded in a 7-coordinate geometry to four equivalent S2- and three equivalent I1- atoms. There are three shorter (2.76 Å) and one longer (2.83 Å) Sm–S bond lengths. All Sm–I bond lengths are 3.33 Å. S2- is bonded to four equivalent Sm3+ atoms to form a mixture of edge and corner-sharing SSm4 tetrahedra. I1- is bonded in a 3-coordinate geometry to three equivalent Sm3+ atoms.
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