Thermochemistry of Gaseous Compounds of Metals.
Abstract
Thermochemical studies of gaseous IIA monohalides CaBr, SrBr, BaBr, and BaCl were carried out by high temperature mass spectrometry. The monohalides were generated by the reaction of HBr or HCl with appropriate metal oxides in molydbenum effusion cells. Dissociation energies and standard heats of formation were evaluated from various equilibrium measurements at temperatures of 1800 to 2000 K. Preliminary thermochemical data were obtained for gaseous BaI. In the course of the work, the gaseous oxybromide OBBr was also observed, and thermochemical data were derived. From studies of the vaporization of CaBr2, SrBr2, and BaBr2 by the torsion-effusion methods, values were derived for the heats of sublimation/vaporization, heats of formation, and dissociation energies of the gaseous dibromides. The derived dissociation energies of the monohalides are compared with values obtained from flame equilibria, chemiluminescence, ionic model calculations, and Birge-Sponer extrapolations; the results provide an interesting comparison of the experimental methods, and give further information about chemical bonding in the monohalides. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1976
- Accession Number
- ADA040222
Entities
People
- D. L. Hildenbrand
Organizations
- SRI International