Thermodynamic data and properties of polyoxometalate Na6V10O28

Owing to their unique structure, polyoxometalates (POMs) are important compounds with both acidic and oxidizing properties that can be used in acid-catalyzed and redox-catalyzed reactions, as well as in medicinal chemistry and as functional materials . Vanadium-based polyoxometalate materials are an important class of POMs, in which Na 6 V 10 O 28 is a common vanadium-based polyoxometalate produced by condensation and dehydration in acidic vanadium-containing solutions. However, the properties of the compound were reported extensively, but thermodynamic data and thermal stability were hardly available. In this study, Na 6 V 10 O 28 material was synthesized by the liquid phase method and characterized by XRD , thermogravimetry , electron microscopy , and infrared analysis. The results show that the prepared material is Na 6 V 10 O 28 ·18H 2 O and its decomposition product was Na 5 V 12 O 32 . The thermodynamic data of Na 6 V 10 O 28 . nH 2 O and Na 5 V 12 O 32 such as heat capacity, entropy, and enthalpy were calculated by the NKR combined with drop calorimetry . Finally, the obtained data were applied to equilibrium thermodynamic calculations for reactions related to Na 6 V 10 O 28 , including condensation reactions, ammonium salt precipitation, thermal decomposition reactions , and hydrolysis precipitation. The results can be used for theoretical calculations of thermodynamic reactions related to Na 6 V 10 O 28 and Na 5 V 12 O 32 .