Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Low temperature heat capacity study of FePO4 and Fe3(P2O7)2

Shi, Q.[Quan], Zhang, L.[Liying], Schlesinger, M. E.[Mark E.], Boerio-Goates, J.[Juliana], Woodfield, B. F.[Brian F.]
J. Chem. Thermodyn. 2013, 62, 35-42
ABSTRACT
The heat capacities of FePO4 and Fe3(P2O7)2 have been measured using a Quantum Design Physical Property Measurement System (PPMS) over the temperature range from (2 to 300)K.The phase transition due to the Fe3+ magnetic ordering in FePO4 has been determined to occur at T = 25.0 K, which agrees well with magnetic measurements reported in the literature. For Fe3(P2O7)2, a Schottky anomaly and a four-peak phase transition have been found below 50 K.The thermodynamic functions, magnetic heat capacities, and magnetic entropies of these two compounds have been calculated based on curve fitting of the experimental heat capacity values. The standard molar entropy at T = 298.15 Khas been obtained to be (122.21 +-1.34) J.K-1.mol-1 and (384.12 +-4.23) J.K-1.mol 1 for FePO4 and Fe3(P2O7)2, respectively.
Compounds
# Formula Name
1 FeO4P iron(III) phosphate
2 Fe3O14P4 iron diphosphate (Fe3(P2O7)2)
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
  • 1
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Gas
  • relaxation calorimetry - Quantum Design PPMS
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Gas
  • relaxation calorimetry - Quantum Design PPMS
  • 1
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • relaxation calorimetry - Quantum Design PPMS
  • 59
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • relaxation calorimetry - Quantum Design PPMS
  • 21
  • POMD
  • 1
  • Molar entropy, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • relaxation calorimetry - Quantum Design PPMS
  • 20
  • POMD
  • 1
  • Molar enthalpy, kJ/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • relaxation calorimetry - Quantum Design PPMS
  • 20
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • relaxation calorimetry - Quantum Design PPMS
  • 65
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • relaxation calorimetry - Quantum Design PPMS
  • 38
  • POMD
  • 1
  • Molar entropy, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • relaxation calorimetry - Quantum Design PPMS
  • 38
  • POMD
  • 1
  • Molar enthalpy, kJ/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • relaxation calorimetry - Quantum Design PPMS
  • 38
  • POMD
  • 2
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Gas
  • relaxation calorimetry - Quantum Design PPMS
  • 1
  • POMD
  • 2
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Gas
  • relaxation calorimetry - Quantum Design PPMS
  • 1
  • POMD
  • 2
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • relaxation calorimetry - Quantum Design PPMS
  • 101
  • POMD
  • 2
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • relaxation calorimetry - Quantum Design PPMS
  • 22
  • POMD
  • 2
  • Molar entropy, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • relaxation calorimetry - Quantum Design PPMS
  • 21
  • POMD
  • 2
  • Molar enthalpy, kJ/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • relaxation calorimetry - Quantum Design PPMS
  • 21
  • POMD
  • 2
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • relaxation calorimetry - Quantum Design PPMS
  • 120
  • POMD
  • 2
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • relaxation calorimetry - Quantum Design PPMS
  • 38
  • POMD
  • 2
  • Molar entropy, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • relaxation calorimetry - Quantum Design PPMS
  • 37
  • POMD
  • 2
  • Molar enthalpy, kJ/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • relaxation calorimetry - Quantum Design PPMS
  • 37