Coordination environment around the lithium cation in solid Li2(EMIm)(N(SO2CF3)2)3 (EMIm=1-ethyl-3-methylimidazolium):: Structural clue of ionic liquid electrolytes for lithium batteries

Crystal structure of Li-2(EMIm)(N(SO2CF3)(2))(3) (EMIm = 1-ethyl-3-methylimidazolium cation) has been determined by single-crystal X-ray diffraction as a structural clue of ionic liquid electrolytes for lithium batteries. Li2(EMIm)(N(SO2CF3)2)3 crystallizes in the space group P2(1)/c, a = 15.184(3) angstrom, b = 11.358(3) angstrom, c = 21.249(5) angstrom, beta = 111.454(12)degrees, Z = 4, V = 3561.18(14) angstrom(3). Two of the three N(SO2CF3)(2) anions have cis-conformations and the third anion shows a trans-conformation. The asymmetric unit contains two crystallographically independent lithium ions and both of them are trigonal-bipyramidally coordinated by five oxygen atoms of N(SO2CF3)(2) anions, forming a two-dimensional network. EMIm cation occupies a space in the network, weakly interacting with the anions. (c) 2006 Elsevier SAS. All rights reserved.