An investigation of the digitized Raman band profiles of aqueous Mg(ClO<inf>4</inf>)<inf>2</inf> - NaSCN solutions

Abstract

Raman spectra, together with factor analysis and band deconvolution procedure, have been used to study formation of magnesium thiocyanate complexes in aqueous solutions at ambient and elevated temperatures. The total salt concentration in solutions, containing different mole ratio of Mg2+ to SCN-, varied between 3.4 and 7.5 mol dm-3. Factor analyses indicated that two linearly independent scattering components in the band envelopes, recorded in the v1 and v3 stretching regions of SCN-, for all solutions with total salt concentration of 3.4 mol dm-3. The appearance of a pseudo-isosbestic point in the area normalized spectra supported this result, as well as the band resolution procedure. The latter revealed the third scattering component in the spectra of solutions with total salt concentration above 3.5 mol dm-3. Resolved components have been assigned to the free thiocyanate, the 1:1 and 1:2 magnesium thiocyanate complexes. The equilibrium constant KC of the 1:1 complex is of an order of 10-1mol dm-3.