FTIR Spectroscopy of Magnesium Tetraborate Solution

Supersaturated aqueous solution of magnesium tetraborate (MgB4Ü7 -ЭНгО), its acidified solu­ tions 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 axe obtained by sub­ tracting FTIR spectrum of water from that of the magnesium borate aqueous solutions. The results showed that various polyborate anions exist in the solutions. The bands of symmetric vibration of the corresponding polyborate anions were indicated and some assignments were tentatively given. Boron concentration and pH of solution are effective on the formations of polyborate anions. The transformations B 5 0 6 ( 0 H ) + O H " + H 2 0 <Ф B 4 0 5 ( O H ) 2 + B(OH) 3 and B(OH) 3 + O H " & B(OH)^ axe main reactions in these solutions.