10.1021/acs.jpcb.7b01034.s002 Joás Grossi Joás Grossi Jorge J. Kohanoff Jorge J. Kohanoff Niall J. English Niall J. English Eduardo M. Bringa Eduardo M. Bringa Mario G. Del Pópolo Mario G. Del Pópolo On the Mechanism of the Iodide–Triiodide Exchange Reaction in a Solid-State Ionic Liquid American Chemical Society 2017 iodide-based room-temperature Liquid Efficient charge transport Hirshfeld charges charge-transfer process energy barriers bond lengths Several bond-exchange events energy paths BMIM crystal state superionic conductors 0.48 eV iodine-swapping process exchange reaction structure calculations 2017-06-21 18:44:56 Dataset https://acs.figshare.com/articles/dataset/On_the_Mechanism_of_the_Iodide_Triiodide_Exchange_Reaction_in_a_Solid-State_Ionic_Liquid/5134654 Efficient charge transport has been observed in iodide-based room-temperature ionic liquids when doped with iodine. To investigate preferred pathways for the iodide (I<sup>–</sup>)-to-triiodide (I<sub>3</sub><sup>–</sup>) exchange reaction and to clarify the origin of this high ionic conductivity, we have conducted electronic structure calculations in the crystal state of 1-butyl-3-methylimidazolium iodide ([BMIM]­[I]). Energy barriers for the different stages of the iodine-swapping process, including the reorientation of the I<sup>–</sup>···I<sub>3</sub><sup>–</sup> moiety, were determined from minimum energy paths as a function of a reaction coordinate. Hirshfeld charges and structural parameters, such as bond lengths and angles, were monitored during the reaction. Several bond-exchange events were observed with energy barriers ranging from 0.17 to 0.48 eV and coinciding with the formation of a twisted I<sup>–</sup>···I<sub>3</sub><sup>–</sup> complex. Striking similarities were observed in the mechanics and energetics of this charge-transfer process in relation to solid-state superionic conductors.