The structures and vibrational spectra for the anions [C(CF3SO2)(3)](-) and [CH(CF3SO2)(2)](-) as well as their ion pairs with lithium have been calculated. Ab initio self-consistent field molecular orbital Hartree-Fock and density functional theory calculations, using the hybrid B3LYP functional, have been performed, both using the 6-31G* basis set. The results are compared with earlier calculational work on the more commonly used TFSI anion, [N(CF3SO2)(2)](-), and with experimental IR spectra. The localization of the single negative charge toward the SO2 groups is slightly less pronounced in the [C(CF3SO2)(3)](-) anion, which results in a lower lithium ion affinity. Also, the double bond character for the central Sx-CI bonds is smaller compared to that of [CH(CF3SO2)(2)](-). The two anions' advantages/disadvantages as polymer electrolyte components are discussed.