PRELIMINARY REPORT ON THE THERMODYNAMIC PROPERTIES OF SELECTED LIGHT- ELEMENT AND SOME RELATED COMPOUNDS
Abstract
This report presents improved values for the heats of formation and some other thermodynamic properties of a number of light-element substances -- resulting from recent NBS experimental studies (calorimetric, vaporization, and spectroscopic) and critical literature review. Methods, results, and earlier published values are discussed critically and in detail. The standard heat of formation of BF3(g) was determined by direct combination of the elements in a bomb calorimeter and with an estimated error of + or -0.5 kcal mol (-1). OF2(g) was found to be endothermic (+5.86 + or -0.3 kcal mol (-1) from flame calorimetry on the reactions of OF2, O2, and F2 with H2. The results of a precise entrainment (transpiration) study of the sublimation of AlF3(c) were combined with published data to give new values for the thermodynamic properties of AlF3(g) and Al2F6(g). A final revised report on high-temperature mass spectrometry of the BeO-BeF2 system discusses interfering ion intensities, and evaluates the heat of sublimation of BeF2(gl) and the standard heat of formation of Be2OF2(g). A quadrupole mass spectrometer appears to have shown that liquid Al2O3 loses oxygen and becomes non-stoichiometric, a result consistent with the earlier NBS discovery of an irreversible change in sublimed Al2O3(c).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1967
- Accession Number
- AD0812108
Entities
People
- Charles W. Beckett
- Thomas B. Douglas
Organizations
- National Institute of Standards and Technology