Carbon–Oxygen Bond Energies and Bond Distances

1958 ◽  
Vol 62 (9) ◽  
pp. 1049-1054 ◽  
Author(s):  
George Glockler
Keyword(s):  
Bond Energies ◽  
Oxygen Bond

A density functional study of the bonding in tertiary phosphine chalcogenides and related molecules

1996 ◽  
Vol 74 (11) ◽  
pp. 2363-2371 ◽  
Author(s):  
Nicole Sandblom ◽  
Tom Ziegler ◽  
Tristram Chivers
Keyword(s):  
Density Functional ◽  
Functional Study ◽  
Single Bond ◽  
Bond Energies ◽  
Tertiary Phosphine ◽  
Functional Theory ◽  
Multiple Bonding ◽  
Back Donation ◽  
Oxygen Bond ◽  
Phosphine Chalcogenides

The nature of the phosphorus–tellurium bond in tertiary phosphine tellurides is not well understood. There is also controversy over the nature of multiple bonding in the lighter chalcogenides and the related ylides and imides. Density functional theory (DFT) was used to investigate the interactions in the molecule, Me3PE (E = O, S, Se, Te, BH3, CH2, NH). The calculated PE bond energies and orbital populations reveal contributions from both σ donation from the phosphine and π back-donation to the phosphine in all of the above cases. Down the group from oxygen to tellurium, the PE bond weakens from 544 kJ mol−1 to 184 kJ mol−1, but multiple bonding becomes more significant with respect to the single bond. For E = BH3, the PB bond energy is 166 kJ mol−1. Trimethylphosphine ylide was found to have a π-bond order of 0.5, while that of trimethylphosphine imine is 0.6. For comparison, the oxides of trimethylamine and trimethylarsine were also calculated to examine the pnictogen–oxygen bond; Me3N does not participate in multiple bonding with oxygen, while the π-bond orders for Me3PO and Me3AsO were calculated as 0.7 and 0.6, respectively. Key words: phosphine chalcogenides, phosphine ylides, phosphine imides, DFT calculations

Significance of Heterogeneous Catalysis of Certain Oxidation Reactions by Oxides in Relation to their Heats of Formation

1971 ◽  
Vol 49 (5) ◽  
pp. 809-812 ◽  
Author(s):  
Ashok K. Vijh ◽  
P. Lenfant
Keyword(s):  
Catalytic Activity ◽  
Heterogeneous Catalysis ◽  
Oxygen Atom ◽  
Band Gap ◽  
Electronic Conductivity ◽  
Heats Of Formation ◽  
Oxidation Reactions ◽  
Bond Energies ◽  
Oxygen Bond ◽  
Gap Values

The significance of previous correlations observed by Morooka et al. between heats of formation per oxygen atom, ΔH0, for oxides and their catalytic activity towards oxidation of some hydrocarbons has been discussed. It has been pointed out that ΔH0 values do not represent metal–oxygen bond energies, as assumed by Morooka and co-workers, but instead signify band gap values for the oxides. The catalytic activity of these oxides must therefore be interpreted in terms of their electronic conductivity and not in relation to the strength of metal–oxygen bond involved.

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