Thermodynamics Research Center / ThermoML | Thermochimica Acta

Determination of the Equilibrium Temperatures and Enthalpies of the Solid-Solid Transitions of Rubidium Nitrate by Differential Scanning Calorimetry

Charsley, E. L., Laye, P. G., Markham, H. M., Hill, J. O., Berger, B., Griffiths, T. T.
Thermochim. Acta 2008, 469, 1-2, 65-70
ABSTRACT
The equilibrium temperatures of the three solid-solid phase transitions of high purity rubidium nitrate have been measured accurately by stepwise heating and by the extrapolation to zero heating rate method. Mean values of 164.9 +- 0.1 deg C (Transition 1), 222.2 +- 0.5 deg C (Transition 2) and 284.0 +- 0.1 deg C (Transition 3) were obtained using two different types of heat flux DSC instruments. The enthalpies of transitions 1 and 2 were determined using both heat flux and power compensated DSC instruments. The mean values were 3.83 +- 0.02 kJ mol-1 (Transition 1) and 3.14 +- 0.03 kJ mol-1 (Transition 2). For Transition 3 the shape of the DSC curve prevented an unequivocal determination of the enthalpy. Values obtained using two alternative interpretations of the DSC peak shape are discussed in the text.
Compounds
# Formula Name
1 NO3Rb rubidium nitrate
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 4
  • Crystal 4
  • Crystal 3
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 3
  • Crystal 3
  • Crystal 2
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 1
  • Molar enthalpy of transition or fusion, kJ/mol ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DSC
  • 1
  • POMD
  • 1
  • Triple point temperature, K ; Crystal 4
  • Crystal 4
  • Crystal 3
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 1
  • Triple point temperature, K ; Crystal 3
  • Crystal 3
  • Crystal 2
  • Air at 1 atmosphere
  • DTA
  • 1
  • POMD
  • 1
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • DTA
  • 1