skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Heat capacities of the alkali feldspars between 350 and 1000 K from differential scanning calorimetry, the thermodynamic functions of the alkali feldspars from 298. 15 to 1400 K, and the reaction quartz + jadeite = analbite

Journal Article · · Am. Mineral.; (United States)
OSTI ID:5352130

The heat capacities, C/sub p//sup 0/ of low albite, analbite, microcline, and high sanidine have been measured between 350 and 1000 K by differential scanning calorimetry. Evaluation of the results of several phase equilibrium studies of the reaction quartz + jadeite = analbite yields -3029.870 +/- 4.200 and -2851.300 +/- 4.200 kJ/mol for the enthalpy and Gibbs free energy of formation, respectively, of jadeite at 298.15 K and 1 bar. The enthalpy of the low albite-analbite transition determined from calorimetry using Amelia albite for low albite underestimates the magnitude of the enthalpy of the transition because Amelia albite is partially disordered (e.g., Holm and Kleppa, 1968).

Research Organization:
Geological Survey, Reston, VA
OSTI ID:
5352130
Journal Information:
Am. Mineral.; (United States), Vol. 66:11-12
Country of Publication:
United States
Language:
English