Raman study of complexation in aqueous solutions of magnesium acetate

Raman spectra of aqueous solutions of magnesium acetate at 293 K have been studied in the concentration range 0.65-3.24 M, as have the Raman spectra of the crystallohydrate Mg(CH3COO)(2) . 4H(2)O. Fourier deconvolution and band fitting techniques have been used to analyse the spectra in three characteristic regions. The gradual evolution of two new components, in addition to the component corresponding to the C-C vibration of the free acetate ion, is observed in the C-C region of the solutions. These are identified as belonging to mono- and bisacetato complexes. In saturated solutions the bisacetato complexes are the dominating metal-ligand species. Their presence is confirmed also by Fourier deconvolution of the in-plane rocking CO2 vibration.