Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Heat capacities, third-law entropies and thermodynamic functions of the negative thermal expansion material Zn2GeO4 from T=(0 to 400) K

Stevens, R.[Rebecca], Woodfield, B. F., Boerio-Goates, J.[Juliana], Crawford, M. K.[Michael K.]
J. Chem. Thermodyn. 2004, 36, 5, 349-357
ABSTRACT
The molar heat capacity of Zn2GeO4, a material which exhibits negative thermal expansion below ambient temperatures, has been measured in the temperature range 0.5(T/K)400. At T=298.15 K, the standard molar heat capacity is (131.86 +/- 0.26) J ? K-1 ? mol-1. Thermodynamic functions have been generated from smoothed fits of the experimental results. The standard molar entropy at T=298.15 K is (145.12 +/- 0.29) J ? K-1 ? mol-1. The existence of low-energy modes is supported by the excess heat capacity in Zn2GeO4 compared to the sums of the constituent binary oxides.
Compounds
# Formula Name
1 GeO4Zn2 Zn2GeO4
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 heat capacity at constant pressure, J/K/mol ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • Vacuum adiabatic calorimetry
  • 115
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • Vacuum adiabatic calorimetry
  • 47
  • POMD
  • 1
  • Molar enthalpy function {Hm(T)-Hm(0)}/T, J/K/mol ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • Vacuum adiabatic calorimetry
  • 47
  • POMD
  • 1
  • Molar entropy, J/K/mol ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • Vacuum adiabatic calorimetry
  • 47
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal
  • Temperature, K; Crystal
  • Pressure, kPa; Crystal
  • Crystal
  • OTHER
  • 114