Surface and Void Space Analysis of the Crystal Structures of Two Lithium Bis(pentafluoroethanesulfonyl)imide Salts

Abstract

Analysis of two crystal structures of lithium bis(pentafluoroethanesulfonyl)imide is presented. Two orientations of the anion, that is a cis and trans orientation, are observed. Both structures exhibit unique interactions leading to the formation of discrete fluorous domains in the solid-state. A notable difference in the F···F interactions is seen when contrasting the two orientations wherein the trans geometry has a higher percentage of fluorine interactions than the cis orientation. The inclusion of water molecules in one of the structures also leads to the formation of a polar domain formed through a series of cyclical hydrogen bonding rings. The two structures allow for a detailed examination of the bond distances and angles involved in the formation of the two structures. Analysis of the void space in the two structures leads to the observation that the trans conformation exhibits notably higher void space as compared with the cis orientation. Hirshfeld surface analysis is used to help rationalize the interactions leading to unique changes in geometries and structure.