High-temperature heat capacity and thermodynamic properties of pyrovanadate PbVO and orthovanadate Pb(VO).

The heat capacities of PbVO and Pb(VO) as a function of temperature in the range 350-965 K have been studied by the differential scanning calorimetry method. The C = f( T) curve for PbVO is described by the equation C = (230.76 ± 0.51) + (73.60 ± 0.50)×10 T − (18.38 ± 0.54)×10 T in the entire temperature range. For Pb(VO), there is a well-pronounced extreme point in the C = f( T) curve at T = 371.5 K, which is caused by the existence of a structural phase transition. The thermodynamic properties of the oxide compounds have been calculated. [ABSTRACT FROM AUTHOR]