Studies of the intermediate phases in the reaction between barium carbonate and aluminium oxide

Abstract

A study was made of the reaction of barium carbonate with aluminium oxide both in a vacuum and in systems open to the atmosphere. Only three compounds of barium, aluminium and oxygen were found, namely BaAl₂O₄, BaAl₁₂O₁₉, and Ba₃Al₂O₆. With the reactants in the molecular ratio 1 : 1 the only solid product was BaAl₂O₄. With the ratios of 1 : 6 and 3 : 1 the barium carbonate reacts first with the aluminium oxide to give the intermediate compound BaAl₂O₄, which then reacts with the excess reactants to give BaAl₁₂O₁₉, or Ba₃Al₂O₆, respectively. The reactions appear to take place as a direct interaction of the carbonate with aluminium oxide since no barium oxide was detectable at any stage. The results are discussed in terms of Tammann temperatures.