Publications

Abstract In the presence of "inert" electrolytes (sodium fluoride, sulfate, carbonate, phosphate) there exists a range of temperatures and thiourea (TU) concentrations (low and high respectively) where two distinct condensed TU monolayers, totally devoid of anions, are observed. The two relevant molecular structures which are suggested rest on the analysis of the following data: (1) E-T-[TU] phase diagrams derived from capacitance measurements, (2) superficial excesses and molecular areas, (3) charge densities, (4) inhibition power, and (5) kinetics displayed by the various phase transitions involved. Anions like ClO- 4, NO- 3, ClO- 3 are only coadsorbed within the gas-like film of TU, with the result that the pure TU condensed regions are squeezed detectably. On the other hand, anions known to interact strongly with Hg (Cl-, Br-, I-, SCN-)_do coadsorb significantly at all potentials. However, pure TU films tend to reappear if the concentration of these anions is lowered sufficiently with respect to that of the surfactant. © 1987.

Abstract The standard (po = 101.325 kPa) molar enthalpies of combustion in oxygen at 298.15 K were measured by static-bomb calorimetry and the standard molar enthalpies of sublimation at 298.15 K were measured by microcalorimetry for each of the three trihydroxybenzenes, 3-methoxycatechol, and 4-nitrocatechol: {A table is presented}. The derived standard molar enthalpies of formation of the gaseous compounds were compared with values estimated assuming that each group, when substituted into the benzene ring, produces a characteristic increment in the enthalpy of formation, with additional corrections for adjacent substituents. © 1986.

Abstract Theoretical calculations of the third virial coefficient for the pure components of all alkali metal vapours have been carried out using recently reported potential energy surfaces for the doublet and quartet states in which the interaction of three 2S ground-state atoms may evolve. The discrepancy between the theoretical and available experimental estimates for those coefficients is pointed out. © 1985.

Abstract At 298.15 K, the following standard molar enthalpies of formation of the crystalline solids were determined by solution-reaction calorimetry, and the enthalpies of sublimation were measured by microcalorimetry. {A table is presented} (PD, pentan-2,4-dionato; piprm, 2,2-dimethylheptan-3,5-dionato; dibm, 2,6-dimethylheptan-3,5-dionato; ibpm, 2,2,6-trimethylheptan-3,5-dionato; dpm, 2,2,6,6-tetramethylheptan-3,5-dionato.) The mean molar bon-dissociation enthalpy <D>(CuO) was related to D(OH) in the enol form of the diketone, and {<D>(CuO)-0.5D(OH), Hl, enol} was found to equal -(41.8 ± 2.0) kJ · mol-1, constant to within experimental error for all these complexes. Accepting {D(OH), Hl, enol} = (400 ± 20) kJ · mol-1, then <D>(CuO) = (158 ± 10) kJ · mol-1 showing a negligible effect of methyl substitution in the ligand l upon <D>(CuO). © 1984.

Abstract The standard (po = 101.325 kPa) molar enthalpies of combustion in oxygen at 298.15 K were measured by static-bomb calorimetry and the standard molar enthalpies of sublimation at 298.15 K were measured by microcalorimetry for 1,2-dihydroxybenzene (catechol) and six alkylsubstituted catechols: {A table is presented}. The increment in the molar enthalpy of formation of the gaseous compound for substitution of alkyl-groups into catechol was found to be approximately the same as the corresponding increment for substitution into benzene. © 1984.