Aggregation of perchlorates in aprotic donor solvents. Part 2.—Alkaline-earth metal perchlorates

Abstract

Non-aqueous solutions of alkaline-earth metal perchlorates M(ClO,), (M = Ba, Sr, Ca, Mg) have been investigated by IR and Raman spectroscopy. The association of M 2 + and ClO,-into mononuclear species M(ClO,), (x = 1 or 2) depends on the cation and on the solvent. In a given solvent the association extent decreases from Ba to Mg. In all cases it has been possible to find at least one associating solvent (ester, cyclic ether) where the association into M(ClO,), is complete. In the associated species the coordination of ClO, can be monodentate (C3,) or bidentate (C,,). The monodentate coordination is the only mode in Mg(C10,), while bidentate coordination is predominent with the other cations. In that case there is a minor proportion of monodentate ClO, groups which decreases from Ca to Ba. The two kinds of coordination are distinguished by the shift Av, of v1 relative to free ClO, -which is either positive (monodentate) or negative (bidentate). This criterion has been established by the investigation of the other vibrational modes of ClO,. Wavenumber shifts and splittings have been correlated to the cation polarizing power. Force constant variations calculated on BaC10, + and LiClO, are correctly interpreted by Lewis structures.

Enhancement in electrical and stability properties of amorphous polymer based nanocomposite electrolyte

“…They are attributed to spectroscopically free ion, contact ion pair and ion aggregates respectively. A change in the symmetry of ClO 4 − from T d → C 3ν has been confirmed in the FTIR spectra of the PS and PNCE films by the presence of E 1 vibrational mode of ClO 4 − anion observed at~481 cm − 1[21].…”

Raman spectroscopic study of lithium and sodium perchlorate association in propylene carbonate-water mixed solvents

“…23 In band fitting of spectra of the solutions with different amounts of water added, a band at 925 cm 1 had to be added, which was done in accordance with band component analysis of lithium and sodium perchlorate solutions in water by Frost et al 24 and Miller and Macklin. 12,13,23,26 Simultaneously with splitting of the 2 band, in the case of bidentate coordination, the appearance of a new band at the low-wavenumber side of the 1 fundamental was observed. We believe that this band is due to the overtone of the 2 perchlorate band in solutions containing water.…”

“…7 The changes in the Raman spectra of the totally symmetric ( 1 ) band of perchlorate anion in LiClO 4 -PC solutions revealed the existence of different contact species, depending on the LiClO 4 concentration. 11 A few years ago Chabanel and co-workers 12,13 extended Raman and IR spectroscopic investigations to solutions of alkali and alkaline earth metal perchlorates in various non-aqueous solvents. 11 A few years ago Chabanel and co-workers 12,13 extended Raman and IR spectroscopic investigations to solutions of alkali and alkaline earth metal perchlorates in various non-aqueous solvents.…”

Ion transport model in exfoliated and intercalated polymer–clay nanocomposites

“…The presence of E 1 (∼487 cm − 1 ) as noticed in Table 2 rules out the possibility of higher ion aggregate formation and provides evidence in favor of lowering of symmetry of ClO 4 − from T d → C 3ν i.e. the presence of uncoordinated ClO 4 − free anion and ion pairs [26].…”