Thermodynamics Research Center / ThermoML | Thermochimica Acta

Phase transitions and reorientational motions in [Al(OS(CH3)2)6](NO3)3 and its deuterated analog

Gorska, N.[Natalia], Inaba, A.[Akira], Szostak, E.[Elzbieta], Mikuli, E.[Edward]
Thermochim. Acta 2012, 533, 66-73
ABSTRACT
Two phase transitions were found in solid [Al(OS(CH3)2)6](NO3)3 at TC1 = 343.1 K by differential scanning calorimetry and at TC2 = 34.3 K by adiabatic calorimetry. The transition at TC1 is accompanied by large thermal hysteresis (ca. 30 K) and a large entropy change (76 J K.1 mol {1), suggesting an order {disorder-type transition, whereas that at TC2 has a considerably smaller entropy change (3.4 J K {1 mol {1). The phase behavior of the deuterated compound is essentially the same. IR and Raman spectroscopy reveals a reduction in symmetry below TC1 and a change in the reorientational dynamics of CH3 groups and NO3 { anions, indicating that the highest temperature phase is orientationally disordered. The transition at TC2 can be explained by a librational soft-mode theory and all complex cations change their orientation in a cooperative manner.
Compounds
# Formula Name
1 C12H36AlN3O15S6 aluminum nitrate, hexa-dimethylsulfoxide
2 C12D36AlN3O15S6 aluminum nitrate, hexa-dimethylsulfoxide-d6
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
  • Air at 1 atmosphere
  • 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
  • Vacuum adiabatic calorimetry
  • 45
  • POMD
  • 1
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • Vacuum adiabatic calorimetry
  • 126
  • POMD
  • 2
  • Triple point temperature, K ; Crystal 2
  • Crystal 2
  • Crystal 1
  • Air at 1 atmosphere
  • Adiabatic calorimetry
  • 1
  • POMD
  • 2
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 2
  • Temperature, K; Crystal 2
  • Pressure, kPa; Crystal 2
  • Crystal 2
  • Vacuum adiabatic calorimetry
  • 46
  • POMD
  • 2
  • Molar heat capacity at constant pressure, J/K/mol ; Crystal 1
  • Temperature, K; Crystal 1
  • Pressure, kPa; Crystal 1
  • Crystal 1
  • Vacuum adiabatic calorimetry
  • 179