Low-temperature heat capacities and entropies at 298.15⁰ K. of diaspore, kaloinite, dickite, and halloysite Entity Report uri icon

DCO ID 11121/7011-3525-4395-5871-CC

year of publication

  • 1961

abstract

  • Thermodynamic data for the hydrated varieties of alumina are sparse, and those for the common clay minerals are virtually nil. This paper partly fills the vacuum by reporting low-temperature heat-capacity measurements and entropy evaluations of diaspore (AlO(OH)) and three clay minerals of the composition Al2Si2O7·2H20 - kaolinite, dickite, and halloysite.
    The heat-capacity measurements were made in the temperature range 51° to 298.15° K., and the entropies were evaluated at 298.15º K. Diaspore has an unusually low heat capacity and entropy compared with boehmite (another mineral of the same chemical composition). The entropies of the three clay minerals differ too little for entropy to be the important factor relating to differences in the thermal stability of these substances.

publication date

  • 1961

issue

  • 5810