Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

A calorimetric and thermodynamic investigation of potassium uranyl tungstate K2[(UO2)(W2O8)]

Lelet, M. I.[Maxim I.], Ogurtsova, O. V.[Olga V.], Suleimanov, E. V.[Evgeny V.], Geiger, C. A.[Charles A.], Depmeier, W.[Wulf], Alekseev, E. V.[Evgeny V.]
J. Chem. Thermodyn. 2013, 57, 430-435
ABSTRACT
A thermophysical and thermochemical investigation of K2[(UO2)(W2O8)] was undertaken. K2[(UO2) (W2O8)] was synthesized by solid-state reaction of KNO3, WO3 and c-UO3 and characterized by X-ray powder diffraction and X-ray fluorescence methods. Its low-temperature heat capacity was measured using adiabatic calorimetry from T = (9 to 329) K. Based on these data, the third law entropy, S , at T = 298.15 K is (423 +- 1) J K 1 mol 1. The enthalpy of formation of K2[(UO2)(W2O8)] was determined using HF solution calorimetry giving DfH (298 K, K2[(UO2)(W2O8)], cr) = (3897 +- 10) kJ mol 1. From the thermophysical and thermochemical results DfG (298 K, K2[(UO2)(W2O8)], cr) = (3645 +- 10) kJ mol 1 is calculated. Smoothed Cp (T) values between T = (0 and 320) K are presented along with values for S and the functions [H (T) H (0)] and [G (T) H (0)].
Compounds
# Formula Name
1 K potassium
2 W tungsten
3 U uranium
4 O2 oxygen
5 K2O10UW2 potassium uranyl tungstate
Datasets
The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type Compound-# Property Variable Constraint Phase Method #Points
  • POMD
  • 5
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • Vacuum adiabatic calorimetry
  • 166
  • RXND
  • 1
  • 2
  • 3
  • 5
  • 4
  • Molar enthalpy of reaction, kJ/mol
  • Solution calorimetry
  • 1