Results for “SmI2”

DOE OSTI2020

Materials Data on SmI2 by Materials Project

SmI2 is Baddeleyite-like structured and crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. Sm2+ is bonded to seven I1- atoms to form a mixture of distorted edge and corner-sharing SmI7 pentagonal bipyramids. There are a spread of Sm–I bond distances ranging from 3.13–3.37 Å. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted trigonal planar geometry to three equivalent Sm2+ atoms. In the second I1- site, I1- is bonded in a 4-coordinate geometry to four equivalent Sm2+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2026

Pressure-Induced Reduction of Dicyanamide by Samarium(II) in a Coordination Polymer

A samarium(II) coordination polymer, [Sm(2.2.2- cryptand)(dca)]I (dca− = dicyanamide), has been prepared from the reaction of SmI2 with tetrabutylammonium dicyanamide and 2.2.2- cryptand. The structure consists of [Sm(2.2.2-cryptand)] 2+ cations bridged by dicyanamide to form corrugated 1D chains. Single crystals of this compound have been studied spectroscopically using UV−vis−NIR and Raman spectroscopy as a function of pressure to reveal a pressureinduced two-electron reduction of dicyanamide by Sm 2+ to cyanide and cyanamide and Sm 3+ between 5 and 8 GPa. High-pressure single-crystal diffraction studies reveal a phase change at 2.6 ± 0.1 GPa, where a polymorph exhibiting a smaller Sm 2+ ···N C bond angle and shorter Sm 2+ ···C distance was observed. These observations provide mechanistic insight into the reduction of dicyanamide into cyanide and cyanamide by pressurized samarium(II).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗