Standard enthalpy of formation of paratungstate B ion H2W12O4210−(aq)

The enthalpy of sodium paratungstate Na10H2W12O42·27H2O(s) dissolved in solution of 1.0 mol dm−3 LiClO4 was measured at 298.15 K using a Calvet twin-vessel microcalorimeter. The standard enthalpy of formation of paratungstate B ion, H2W12O4210−(aq), was calculated on the basis of the experimental results. Combining this with values from the literature led to ΔfHm0 (H2W12O4210−, aq, 298.15 K)=−(11653.5±10.9) kJ mol−1.