Heat capacity and entropy of rutile (tTiO2).and nepheline (NaAlSiO4).

D. de Ligny (1) , Pascal Richet (1) , E.F. Westrum (2) , Jacques Roux (3)

1 PG - Physique des géomatériaux
2 Department of Chemistry, University of Michigan
3 ISTO - Institut des Sciences de la Terre d'Orléans

From heat capacities measured adiabatically at low temperatures, the standard entropies at 298.15 K of synthetic rutile (TiO2) and nepheline (NaAlSiO4) have been determined to be 50.0 ± 0.1 and 122.8 ± 0.3 J mol−1 K, respectively. These values agree with previous measurements and in particular confirm the higher entropy of nepheline with respect to that of the less dense NaAlSiO4 polymorph carnegieite.

Keywords: Rutile · Nepheline · Heat capacity Entropy

Domains: Sciences of the Universe [physics]; Earth Sciences; Geophysics [physics.geo-ph]

D. de Ligny, Pascal Richet, E.F. Westrum, Jacques Roux. Heat capacity and entropy of rutile (tTiO2).and nepheline (NaAlSiO4).. Physics and Chemistry of Minerals, 2002, 29, pp.267-272. ⟨10.1007/s00269-001-0229-z⟩. ⟨hal-00072618⟩