Definition
Activation parameters are used in chemical kinetics to describe the equilibrium between reactants of a chemical reaction and a single, unstable molecule called a transition state.
Transition State Theory and Elementary Versus Overall Reactions
Transition-state theory is the central underpinning of all chemical kinetics . It postulates that for elementary reactions, there is equilibrium between reactants and an unstable form called the transition state, which is a single molecule. The equilibrium is conventional in all ways except that the transition state has a loose vibrational mode that dissociates and leads to products (Glasstone et al. 1941). The thermodynamic terms that describe this activated equilibrium between the reactants and the transition state are called activation parameters and have exact analogues with the standard thermodynamic parameters that describe a conventional equilibrium between the reactants and the products in a reaction. However, the transition...
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in via an institution.
References
Boudart M (1976) Consistency between kinetics and thermodynamics. J Phys Chem 80:2869–2870
Boudart M, Djega-Mariadasson G (1984) Kinetics of heterogeneous catalytic reactions. Princeton University Press, Princeton. 242 pp
Casey WH, Rustad JR (2016) Pathways for oxygen-isotope exchange in two model oxide clusters. New J Chem 40:898–905
Casey WH, Sposito G (1992) On the temperature dependence of mineral dissolution rates. Geochim Cosmochim Acta 56:3825–3830
Glasstone S, Laidler KJ, Eyring H (1941) The theory of rate processes. Princeton University, New York
Helm L, Merbach AE (2005) Inorganic and bioinorganic solvent exchange mechanisms. Chem Rev 105:1923–1959
Lichtner PC (2016) Kinetic rate laws invariant to scaling the mineral formula unit. Am J Sci 316:437–469
Rustad JR (2010) Elementary reactions in polynuclear ions and aqueous-mineral interfaces: a new geology. Adv Inorg Chem 62:391–436
Rustad JR, Casey WH (2012) Metastable structures and isotope exchange reactions in polyoxometalate ions provide a molecular view of oxide dissolution. Nat Mater 11:223–226
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2016 Springer International Publishing AG
About this entry
Cite this entry
Casey, W.H., Ohlin, C.A. (2016). Activation Parameters: Energy, Enthalpy, Entropy, and Volume. In: White, W. (eds) Encyclopedia of Geochemistry. Encyclopedia of Earth Sciences Series. Springer, Cham. https://doi.org/10.1007/978-3-319-39193-9_48-1
Download citation
DOI: https://doi.org/10.1007/978-3-319-39193-9_48-1
Received:
Accepted:
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-39193-9
Online ISBN: 978-3-319-39193-9
eBook Packages: Springer Reference Earth and Environm. ScienceReference Module Physical and Materials ScienceReference Module Earth and Environmental Sciences