Thermodynamics Research Center / ThermoML | Thermochimica Acta

Thermodynamics of BaNd2Fe2O7(s) and BaNdFeO4(s) in the system Ba Nd Fe O

Rakshit, S. K., Parida, S. C., Dash, S., Singh, Z.[Ziley], Venugopal, V.
Thermochim. Acta 2006, 443, 1, 98-104
ABSTRACT
Two compounds, BaNd2Fe2O7(s) and BaNdFeO4(s) in the quaternary system Ba Nd Fe O were prepared by citrate nitrate gel combustion route and characterized by X-ray diffraction analysis. Heat capacities of these two oxides were measured in two different temperature ranges: (i) 130 325K and (ii) 310 845 K, using a heat flux type differential scanning calorimeter. Two different types of solid-state electrochemical cells with CaF2(s) as the solid electrolyte were employed to measure the e.m.f. as a function of temperature. The standard molar Gibbs energies of formation of these quaternary oxides were calculated as a function of temperature from the e.m.f. data. The standard molar enthalpies of formation from elements at 298.15 K, dfH.m (298.15 K) and the standard entropies, S.m (298.15 K) of these oxides were calculated by the second law method. The values of dfH.m (298.15 K) and S.m (298.15 K) obtained for BaNd2Fe2O7(s) are: -2756.9 kJ mol-1 and 234.0 JK-1 mol-1 whereas those for BaNdFeO4(s) are: -2061.5 kJ mol-1 and 91.6 JK-1 mol-1, respectively.
Compounds
# Formula Name
1 CaO calcium monoxide
2 BaF2 barium difluoride
3 CaF2 calcium fluoride
4 FeNdO3 neodymium ferrite
5 BaFe2Nd2O7 barium iron neodymium oxide (BaFe2Nd2O7)
6 BaFeNdO4 barium iron neodymium oxide (BaFeNdO4)
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
  • Mass density, kg/m3 ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • X-ray diffraction
  • 1
  • POMD
  • 5
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • Small sample (50 mg) DSC
  • 64
  • POMD
  • 6
  • Mass density, kg/m3 ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • X-ray diffraction
  • 1
  • POMD
  • 6
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • Small sample (50 mg) DSC
  • 66
  • RXND
  • 1
  • 2
  • 3
  • 5
  • 6
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 1
  • RXND
  • 1
  • 2
  • 3
  • 5
  • 6
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 1
  • RXND
  • 1
  • 2
  • 3
  • 4
  • 5
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 1
  • RXND
  • 1
  • 2
  • 3
  • 4
  • 5
  • Molar Gibbs energy of reaction, kJ/mol
  • Calculated from EMF cell potential
  • 1