COMMISSION ON THERMODYNAMICS
(I.2)
Number: 120/15/95
Title: Thermochemistry
of chemical reactions: nomenclature, symbols and experimental methods
for bond energies
Coordinator(s): M.
Ribeiro da Silva
Objective:
Nomenclature and symbolism for bond energies are, at the moment, somewhat
confusing although these quantities are widely used to estimate the
thermochemistry of species for which the enthalpies of formation are
unknown. The proliferation of designations and symbols for quantities
variously known as bond strengths, bond enthalpies, bond energies,
bond dissociation enthalpies, bond enthalpy terms, stepwise bond dissociation
energies, intrinsic bond energies, BDE,D etc clearly requires some
standardisation. Several experimental techniques are available to
determine the parameters named above but can only be used to study
the thermochemistry of long-lived molecules. However, modern techniques
have made possible the study of these species. The correct relationship
between the quantities measured with some of these new techniques
and thermodynamic functions are often not straightforward and deserve
a careful analysis. It is therefore proposed that this project considers
in the first stage a comprehensive list of methods that have been
used to derive energetic data. A second stage will involve a description
of each method with an analysis of its basic assumptions and how thermodynamic
data can be derived. In addition recommendations of standard nomenclature
and symbols for bond energetics would be prepared.
Progress:
Progress in the first two years has been very good. A draft of the
basic information to be included in the report has already been circulated
for approval. In the next period comments will be incorporated and
the descriptive material added.
A draft of the paper has been
now prepared and is awaiting final comments before being submitted
for publication.
A manuscript is being prepared
for publication in Pure Appl. Chem. A final document is submitted
to public review comments until 30 September 2002. >
see provisional recommendations
[../../reports/provisional/abstract02/ribeiro-da-silva_300902.html}
Dec 2007 - a revised draft is being finalized
and shall be available mid 2008.
July 2008 - A draft titled 'Thermochemistry of
Chemical Reactions: Terminology and Symbols' is submitted to public
review comments until 30 December 2008 > see provisional
recommendations
Last Update: 30 July
2008