Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Investigation in the variation of Gibbs energy of formation of RE6UO12 (RE = La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, Lu) along the 4f series

Sahu, M.[Manjulata], Kumari, K.[Khushboo], Saxena, M.K., Dash, S.[Smruti]
J. Chem. Thermodyn. 2019, 138, 374-386
ABSTRACT
The RE6UO12 (s) (RE = La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, Lu) compounds were synthesized by citrate nitrate combustion method and characterized by X-Ray Diffraction (XRD) technique. Standard molar Gibbs energy of formation of RE6UO12(s) (RE = La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, Lu) was determined from the equilibrium electromotive force (e.m.f) data obtained from solid-state Galvanic cell with oxide ion conducting yttria-stabilized-zirconia (YSZ) electrolyte. The cells were operated under high pure argon atmosphere. E.m.f. measurements were carried out in the temperature range of 850 1150 K. Phase transition in Sm6UO12(s) and Yb6UO12(s) were detected at 1125 K and 1065 K, respectively. The transition temperatures were confirmed from high temperature XRD technique. The standard enthalpy of formation and entropy at temperature of 298.15 K for RE6UO12 (s) was calculated from the Gibbs energy data using second and third law analysis and the data were compared with the corresponding data reported for RE2O3(s). Similar trend in enthalpy as well as entropy was observed for RE6UO12 (s) and RE2O3 (s) along the series of 4f elements.
Compounds
# Formula Name
1 La lanthanum
2 U uranium
3 O2 oxygen
4 Nd neodymium
5 Sm samarium
6 Eu europium
7 Gd gadolinium
8 Tb terbium
9 Dy dysprosium
10 Ho holmium
11 Tm thulium
12 Yb ytterbium
13 Lu lutetium
14 La6O12U lanthanum uranium oxide
15 Nd6O12U neodymium uranium oxide (Nd6UO12)
16 O12Sm6U samarium uranium oxide
17 Eu6O12U europium uranium oxide
18 Gd6O12U gadolinium uranium oxide (Gd6UO12)
19 O12Tb6U terbium uranium oxide (Tb6UO12)
20 Dy6O12U dysprosium uranium oxide (Dy6UO12)
21 Ho6O12U holmium uranium oxide (Ho6UO12)
22 O12Tm6U thulium uranium oxide (Tm6UO12)
23 O12UYb6 uranium ytterbium oxide (Yb6UO12)
24 Lu6O12U lutetium uranium oxide (Lu6UO12)
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
  • 16
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • Combination of emf and XRD measurements
  • 1
  • POMD
  • 23
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • Combination of emf and XRD measurements
  • 1
  • RXND
  • 1
  • 2
  • 14
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 16
  • RXND
  • 4
  • 2
  • 15
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 16
  • RXND
  • 5
  • 2
  • 16
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 12
  • RXND
  • 6
  • 2
  • 17
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 14
  • RXND
  • 7
  • 2
  • 18
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 12
  • RXND
  • 8
  • 2
  • 19
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 14
  • RXND
  • 9
  • 2
  • 20
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 9
  • RXND
  • 10
  • 2
  • 21
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 15
  • RXND
  • 11
  • 2
  • 22
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 14
  • RXND
  • 2
  • 12
  • 23
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 6
  • RXND
  • 13
  • 2
  • 24
  • 3
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 18