Collect. Czech. Chem. Commun. 1984, 49, 2355-2362

Acid-base properties of metals and glasses of Na2O.P2O5-xB2O3 system

Juraj Leškoa, Marie Doruškováb and Jan Tržilb

a Institute for Metallurgy Processes Theory, Czechoslovak Academy of Sciences, 703 00 Ostrava
b Department of Chemistry, Mining Institute, 708 00 Ostrava


Boron oxide in the Na2O.P2O5-x B2O3 system behaves as a Lux base. Its addition to Na2O.P2O5 brings about transformation of a Co(II) indicator from octahedral to tetrahedral configuration, increase in the optical basicity ΛPb(II), increase in the relative basicity of the melt as determined by means of a galvanic cell, and depolymerization reactions releasing PO43- ions. In the Na2O-B2O3 system free of P2O5, boron oxide behaves as a Lux acid. The amphoretic nature of B2O3 is explained in terms of Lux's acid-base theory extended in analogy with the protolysis theory. The theoretical optical basicity values do not indicate the amphoretic behaviour of B2O3 because in this approach boron oxide is a priori regarded as more acidic than Na2O.P2O5.