Thermochemistry of Gaseous Compounds of Metals.
Abstract
Thermochemical studies of a number of gaseous metal halides and oxides have been carried out by high temperature mass spectrometry, including CaI, SrI, BaI, EuF, EuF2 and SmO. Dissociation energies and heats of formation are derived from the data, and the results are compared with the predictions of several theoretical models where possible. For the IIA metal iodides, the experimental dissociation energies follow trends established by the fluorides, chlorides and bromides; the results are compatible with corrected Birge-Sponer extrapolations and with electrostatic model calculations. The data for BaI suggest that chemiluminescent spectra resulting from the Ba + I2 reaction may be due in part to the reaction of electronically-excited Ba atoms. Sublimation data for CaI2(s), and vaporization data for SrI2(l) and BaI2(l) obtained by the torsion-effusion method are consistent with estimated molecular parameters of the gaseous diodide molecules, leading to accurate thermochemical data for these molecules. The results for SmO resolve a long-standing discrepancy between the dissociation energies of SmO and EuO. And finally, torsion-effusion studies of the dissociative vaporization of PbF2(s) yielded new thermochemical data for PbF4(g).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1977
- Accession Number
- ADA035704
Entities
People
- D. L. Hildenbrand
Organizations
- SRI International