Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Heat capacity and order-disorder phase transition in negative thermal expansion compound ZrW2O8

Yamamura, Y.[Yasuhisa], Tsuji, T.[Toshihide], Saito, K.[Kazuya], Sorai, M.[Michio]
J. Chem. Thermodyn. 2004, 36, 6, 525-531
ABSTRACT
Heat capacity of ZrW2O8 was measured in the (1.8 to 483) K temperature range by using two adiabatic and a commercial relaxation calorimeters. Standard thermodynamic functions of ZrW2O8 were estimated from the measured molar heat capacity. A large -type anomaly of heat capacity due to an order-disorder phase transition was observed at T=(440+/- 0.5) K. The enthalpy and entropy of phase transition were determined to be (1.56 +/- 0.01) kJ ? mol-1 and (4.09 +/- 0.03) J ? K-1 ? mol-1, respectively. The magnitude of the entropy of transition supports the order-disorder mechanism previously suggested by the present authors.
Compounds
# Formula Name
1 O8W2Zr zirconium 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
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Gas
  • Adiabatic calorimetry
  • 1
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • VADIAC:UFactor:2
  • 197
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • VADIAC:UFactor:2
  • 52
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • VADIAC:UFactor:2
  • 215
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • VADIAC:UFactor:2
  • 45
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • VADIAC:UFactor:2
  • 4
  • POMD
  • 1
  • Molar enthalpy function {Hm(T)-Hm(0)}/T, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • VADIAC:UFactor:2
  • 45
  • POMD
  • 1
  • Molar enthalpy function {Hm(T)-Hm(0)}/T, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • VADIAC:UFactor:2
  • 4
  • POMD
  • 1
  • Molar entropy, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • VADIAC:UFactor:2
  • 45
  • POMD
  • 1
  • Molar entropy, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • VADIAC:UFactor:2
  • 4