The Interaction of Barium (II) cations with sodium orthotungstate solution at different acidity value

Abstract

Interactions between isopolytungstate anions in aqueous solution Ba2+ – WO4 2– (Z = 1.00) – H+ / OH– – H2O at CW = 0.01 mol/L studied in the master's work by pH-potentiometric titration method under the ionic strength I = 0.10 mol/L, which was followed by mathematical modeling in the CLINP 2.1 program. A model which included ion pairs between the barium (II) cations and paratungstate B – anion was chosen as an adequate experiment description: Ba2+ , [W12O40(OH)2] 10– Ba2+ , [HW12O40(OH)2] 9– , Ba2+ , [H2W12O40(OH)2] 8– , Ba2+ , [H3W12O40(OH)2] 7– . Concentration constants logarithms were calculated for these ion pairs. From acidified to different acidity values solution of the Na2WO4 barium (II) paratungstates B were synthesized: Ba5[W12O40(OH)2]·30H2O (Z = 1.17), Na6Ba2[W12O40(ОН)2]·28Н2О (Z = 1.25), Na2Ba4[W12O40(ОН)2]·25Н2О (Z = 1.33). The composition of the isolated salts was determined by the results of IRspectroscopy and chemical elemental analysis.