Structure of LiN(CF3SO2)2, a novel salt for electrochemistry

Abstract

The crystal structure of lithium bis(trifluoromethanesulfonimide)[LiN(CF₃SO₂)₂] has been solved from X-ray powder diffraction data and refined by the Rietveld method. The salt crystallises in the orthorhombic system, space group Pnaa, a= 9.6351(2)Å, b= 5.4154(1)Å, c= 16.2639(3)Å. The anion, previously uncharacterised crystallographically, has two-fold symmetry around the nitrogen atom, with short [1.56(1)Å] S—N distances and a large S—N—S angle [129(1)°]. This is consistent with other similar salts and suggests a high degree of double-bond character and delocalisation around N. Li⁺ is tetrahedrally coordinated by four oxygens from four neighbouring anions.