FTIR spectroscopy of magnesium tetraborate solution

Supersaturated aqueous solution of magnesium tetraborate (MgB4O7 . 9H(2)O), its acidified solutions with azeotropic hydrochloric acid, and its diluted solutions with water have been recorded by differential FTIR spectra. The differential FTIR spectra of borate in solutions are obtained by subtractin g FTIR spectrum of water from that of the magnesium borate aqueous solution s. The results showed that various polyborate anions exist in the solutions . The bands of symmetric vibration of the corresponding polyborate anions w ere indicated and some assignments were tentatively given. Boron concentrat ion and pH of solution are effective on the formations of polyborate anions . The transformations B5O6(OH)(4)(-) + OH- + H2O double left right arrow B4 O5(OH)(4)(2-) + B(OH)(3) and B(OH)(3) + OH- double left right arrow B(OH)(4 )(-) are main reactions in these solutions.