Ab initio SCF study on LiClO4 and Li2SO4 molecules: geometries and vibrational frequencies.

The coordination structures of the mols. LiClO4 and Li2SO4 were studied by ab initio SCF calcns. carried out at the 3-21G*, 6-31G*, and DZP basis sets level; the geometries of ClO4- and SO42- were detd. at the 3-21G*, 6-31G*, 6-31 + G*, DZP and TZP levels. LiClO4 and Li2SO4 prefer at all the levels of the HF-SCF theory bidentate structures of C2v and D2d symmetries, resp. The tridentate and monodentate C3v symmetry structures of LiClO4, and the C2v and tridentate C3v ones of Li2SO4 were also considered in detail. Harmonic frequencies of vibration of the anions and of each coordination model of LiClO4 and Li2SO4 as well as the 18O spectra of LiClO4 (C2v symmetry) and Li2SO4 (D2d symmetry) are reported and commented on using the exptl. IR spectroscopy results.