title: Deuterium NMR and differential scanning calorimetric studies of the calcium salts of rhodium and iridium pentadeuterides, Ca2RhD5 and Ca2IrD5.
abstract: The deuterium NMR spectra of the ternary metal deuterides (TMDs) Ca(2)RhD(5) and Ca(2)IrD(5) show that the disorder is dynamic at room temperature, with barriers to the motion of 31.8 and 39.0 kJ mol(-1), respectively. At low temperatures, splittings equivalent to quadrupole coupling constants of 50.9 and 24.5 kHz were obtained for Ca(2)RhD(5) and 68.3 and 41.7 kHz for Ca(2)IrD(5) and are assigned to the planar and apical deuterium positions, respectively. Differential scanning calorimetric study of the transition in Ca(2)IrH(5) located a reversible phase transition at 284 K with an enthalpy change of 650 J mol(-1) and entropy change of 2.3 J K(-1) mol(-1).
authors.affiliation: Department of Chemistry, McGill University, 801 Sherbrooke Street, W., Montreal, QC H3A 2K6 Canada. denis.gilson@mcgill.ca
authors.forename: Denis F R
authors.initials: DF
authors.lastname: Gilson
authors.forename: Frederick G
authors.initials: FG
authors.lastname: Morin
authors.forename: Ralph O
authors.initials: RO
authors.lastname: Moyer