Determination of carbide, carbyne, and carbene bond energies by gas-phase photodissociation of RhCH2+, NbCH2+, and LaCH2+

1987 ◽  
Vol 109 (12) ◽  
pp. 3543-3548 ◽  
Author(s):  
R. L. Hettich ◽  
Ben S. Freiser
Keyword(s):  
Gas Phase ◽  
Bond Energies

The hydrogen bond energies of the bihalide ions XHX− and YHX−

1985 ◽  
Vol 63 (7) ◽  
pp. 1399-1406 ◽  
Author(s):  
G. Caldwell ◽  
P. Kebarle
Keyword(s):  
Hydrogen Bond ◽  
Gas Phase ◽  
Free Energies ◽  
Bond Energies ◽  
Solvation Energies ◽  
Complete Set ◽  
Lattice Energies ◽  
Gas Phase Ion ◽  
Hydrogen Bond Energies

Experimental measurements of the gas phase ion equilibria X− + HX = XHX−, X−(HX)n−1 + HX = X−(HX)n, and X− + HY = XHY where X, Y = Cl, Br, I, with a high pressure mass spectrometer, combined with the recent determination of F− + HF = FHF− by Larson and McMahon, provide a very complete set of hydrogen bond dissociation enthalpies and free energies for the hydrogen bihalide ions. The bond energy trends in the different XHX− and XHY− are discussed. The data can be used also for the evaluation of lattice energies of salts containing the bihalide ions and for determinations of the solvation energies of these ions.

scholarly journals THERMODYNAMIC PROPERTIES OF ORGANIC ACIDS AND SOME THEIR DERIVATIVES

2019 ◽  
Vol 62 (11) ◽  
pp. 38-45
Author(s):  
Vitaly V. Ovchinnikov ◽  
Alexey A. Kulakov ◽  
Irina G. Grigor′eva ◽  
Svetlana A. Maltseva
Keyword(s):  
Experimental Data ◽  
Organic Acids ◽  
Gas Phase ◽  
Thermodynamic Functions ◽  
Bond Energies ◽  
Additional Material ◽  
Electron Pairs ◽  
Valence Electrons ◽  
Heats Of Combustion

The heats of vaporization, combustion, formation, entropy and the heat capacities in different phases of different carbonic acids and their derivatives: acetates, esters with fatty radicals, two-, three- and four-basic acids (52 compounds) were analysed in the framework of one-parametric mathematic equations. The experimental data of all chosen one-, two-, three- and four-basic acids were analyzed. It was determined, that all thermodynamic functions of these types of compounds depend on the number of valence electrons N, from which the sum of lone electron pairs g as represented in the equations Δvap,c,fH° = i ±  f (N-g) and S°(Cp) = i ±  f (N-g) is excluded. The coefficients f in the first equations is in the range of 104-113 kJ mol-1 electron-1, that corresponds to the same values f in the equations, which are mentioned in our earlier papers on the determination of the heats of combustion of organic acids. As concerned of coefficient i in the received equations, necessary to note that situation is not synonymous as with the coefficient f. The magnitudes of this coefficient are different in the equations of vaporization, combustion, formation also as in the equations of entropy and the heat of capacity. On the base of literary experimental data we calculated the 29 new equations, which can be used for the calculation of the same thermodynamic functions for other new organic acids and especially bioorganic substances with the useful properties. Necessary to add, that the received equations can serve as additional material for the calculation of the bond energies of fatty acids and their derivatives in gas phase.

The Hydrogen Bond Energies in ClHCl− and Cl−(HCl)n

1974 ◽  
Vol 52 (13) ◽  
pp. 2449-2453 ◽  
Author(s):  
R. Yamdagni ◽  
P. Kebarle
Keyword(s):  
Gas Phase ◽  
Equilibrium Constants ◽  
Bond Energies ◽  
Gas Phase Reactions ◽  
Weakly Bound ◽  
Pulsed Electron Beam ◽  
Large N ◽  
Different Temperatures ◽  
Hydrogen Bond Energies

The equilibrium constants for the gas phase reactions: Cl−(HCl)n = Cl−(HCl)n−1 + HCl, (n, n−1) were measured at different temperatures with a pulsed electron beam high pressure mass spectrometer. This allowed determination of ΔGn,n−10, ΔHn,n−10, and ΔSn,n−10 for reactions with n = 1 to n = 4. The enthalpy change for the reaction: (ClHCl)− = Cl− + HCl was ΔH1.00 = 23.7 kcal/mol. This value is much higher than the literature value of 14.2 kcal/mol based on Born cycles. The stabilities of the Cl−(HCl)n clusters are compared with those of OH−(H2O)n and Cl−(H2O)n measured earlier. It is found that the (ClHCl)− is nearly as stable as the (HOHOH)− species but that the stabilities of the higher Cl−(HCl)n clusters decreases much more rapidly than that of OH−(H2O)n. The initial strong interaction in (ClHCl) is assumed to be due to the high polarizability of Cl. For large n this effect becomes unimportant. Cl−HOH is much more weakly bound than (ClHCl)−, however, at high n the Cl−(H2O)n interactions become more favorable.

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