Publications

Abstract The effect of temperature on the differential capacity versus potential curve and the potential of zero charge was measured for a gold (100) face electrode in contact with solutions of HClO4. A small shift of the potential of the capacity minimum with concentration was observed, pointing to slight adsorption of perchlorate ions at zero charge. The sign of the temperature coefficient of the potential of zero charge and the variation of the entropy of formation of the interface with charge density are interpreted in terms of the interactions of the gold surface with the solvent. The sign of the temperature coefficient of the inner layer capacity at zero charge was found to be positive. © 1990.

Abstract The standard (po = 0.1 MPa) molar enthalpies of combustion, in oxygen, at 298.15 K, were measured by static bomb calorimetry for three 8-hydroxyquinolines; the vapour pressures of the crystals were measured as functions of temperature by the Knudsen-effusion technique, and the standard molar enthalpies of sublimation, at 298.15 K, were derived by the Clausius-Clapeyron equation. Direct measurements of the standard molar enthalpies of sublimation using micro-calorimetry confirmed the values from the Knudsen technique. {A table is presented}. © 1989.

Abstract The standard (po = 0.1 MPa) molar enthalpies of combustion in oxygen at 298.15 K were measured by static-bomb calorimetry for some quinones and dihydroxyquinones. The standard molar enthalpies of sublimation at 298.15 K were measured by microcalorimetry for 1,4-naphthoquinone and 9,10-phenanthraquinone; values were selected from the literature for the remaining compounds in order to derive the standard molar enthalpies of formation in the gaseous state. {A table is presented}. The energies of the intramolecular hydrogen bonds in the dihydroxyquinones were assessed as (25 ± 3) kJ·mol-1. 1,4,9,10-Anthradiquinone is apparently considerably strained, and although its reaction with water produces 1,4-dihydroxy-9,10-anthraquinone, a concomitant formation of hydrogen peroxide is shown to be thermodynamically improbable. © 1989.

Abstract The standard (po = 0.1 MPa) molar enthalpies of combustion in oxygen at 298.15 K of crystalline thiobenzamide, N, N-dimethylthiobenzamide, and N, N-diethylthiobenzamide to produce CO2(g), N2(g), and H2SO4·115H2O(l) were measured by rotating-bomb calorimetry. The standard molar enthalpies of sublimation at 298.15 K were measured by microcalorimetry. {A table is presented}. These results form the basis of a bond-energy scheme to estimate ΔfHmo(C6H5CSNr2, g). © 1989.

Abstract The standard (po=0.1 MPa) molar enthalpies of combustion 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 three benzylidene t-butylamine N-oxide derivatives and for 4-nitrobenzylidine t-butylamine: {A table is presented}. From the standard molar enthalpies of formation of the gaseous compounds, the molar dissociation enthalpies of the (NO) bonds were derived, and these were found to be constant within experimental error to give a weighted mean value: D(NO)/(kJ·mol-1) = (285.9 ± 3.6). © 1989.

Abstract The trajectory calculations of the alkali-metal atom + alkali-metal dimer reactions initiated in a previous work have been extended to the Li + Li2 system using two different potential-energy surfaces for the Li3 trimer. The results agree well with each other and with previous results by other authors, suggesting a statistical mechanism for this exchange reaction.

Abstract The behaviour of two crystal faces of gold with extreme surface energies (111) and (210) in aqueous solutions of sulphamic acid was studied. The results indicate the influence of crystallographic orientation (c.o.) in the adsorption of sulphamic acid. The degree of adsorption is intermediate between perchlorate and sulphate, and is reflected on the oxidation process of gold single crystal faces. The results are interpreted in terms of the distortion of the trigonal structure of the anion. © 1989.

Abstract The standard molar enthalpies of formation, at 298.15 K, of five crystalline bent metallocenes, [M(η-C5H5)2L] (M = Mo, W, Ti) (LH2 = 1,2-benzenediol, C6H4-(OH)2; 2,3-napthalenediol, C10H6(OH)2; 9,10-phenanthrenediol, C14H8(OH)2), have been derived from enthalpies of hydrolyses in acid solution measured by precision solution-reaction calorimetry. The results were: ΔHf° [Mo(η-C5H5)2(O26H4),c] = -130.6±2.9, ΔHf°[Mo(η-C5H5)2(O2C10H6),c] = -80.3± 2.2, ΔHf° [ Mo(η-C5H5)2(O2C14H8,c] = -53.25 ± 10.4, ΔHf° [ W(η-C5H5)2 (O2C6H4),c] = -112.8 ±2.9, ΔHf° [Ti(η-C5H5)2(O2C14H8),c] = -322.6 ± 12.7 kJ mol-1. The metaloxygen bond strengths were evaluated as mean bond enthalpy terms (E). Comparison with corresponding values in similar comlexes reveals that small steric energy arises from the binding of a catechol type ligand to a metal atom. © 1988.