Thermodynamics Research Center / ThermoML | Thermochimica Acta

Thermodynamic stability of Sm2TeO6

Balakrishnan, S., Pankajavalli, R., Ananthasivan, K., Anthonysamy, S.
Thermochim. Acta 2008, 467, 1-2, 80-85
ABSTRACT
The vapour pressure of Sm2TeO6 was measured using a thermal analyzer with a horizontal arm. This TG based transpiration technique, was validated by measuring the vapour pressure of pure TeO2. Temperature dependence of the latter was measured to be log p (Pa) (. 0.03) = 14.2 - 13321 / T(K) in the range 884 987 K. These data yielded a 0 .H298 value of 269.7 . 0.6 kJ mol 1 for the enthalpy of sublimation (third-law method) of TeO2 which compared well with the data reported in the literature. The temperature dependence of vapour pressure of TeO2 over the mixture Sm2TeO6 (s) + Sm2O3(s) generated by the incongruent vapourisation reaction, Sm2TeO6 (s) . Sm2O3(s) + TeO2(g) +1/2O2(g) could be expressed as log p (Pa) . .18.92 . 25969 / T (K). . 0.06 ( 1374 .1543 K ) The standard Gibbs energy of formation of Sm2TeO6 (s) was derived by using the above vapour pressure data in conjunction with auxiliary data for the other coexisting phases. The temperature dependence of the Gibbs energy of formation of Sm2TeO6 could be represented as . . 1 2 6 0f .G (Sm TeO ) . - 2408.8 . 0.5783T (K) . 5.8 kJ mol. Data on the Gibbs energy of formation of Sm2TeO6 (s) are reported in this study for the first time.
Compounds
# Formula Name
1 O2Te tellurium dioxide
2 O3Sm2 samarium oxide (Sm2O3)
3 O2 oxygen
4 O6Sm2Te telluric acid (H6TeO6), samarium(3+) salt (1:2)
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
  • Vapor or sublimation pressure, kPa ; Crystal
  • Temperature, K; Crystal
  • Crystal
  • Gas
  • Transpiration method
  • 21
  • RXND
  • 1
  • 2
  • 4
  • 3
  • Thermodynamic equilibrium constant
  • Dynamic equilibration
  • 16