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  • Poster presentation
  • Open Access

Applying the unified pH scale: absolute acidities in the gas phase and anchor points for eleven representative liquid media

Journal of Cheminformatics20124 (Suppl 1) :P8

  • Published:


  • Acidity
  • Quantum Chemical
  • Solvation Energy
  • Solvation Model
  • Bulk Phasis

The investigations on our recently introduced unified acidity scale [1] based on the absolute chemical potential of the proton pointed out the inadequateness of the established GA scale. Earlier it was inter alia found that, when trying to correlate pKa with GA values, in several cases the correlation was broken without any sufficient explanation [2, 3]. However, the GA does not take into account the pressure dependent speciation in the gas phase. In this contribution we systematically extend the theory of acidity in the gas phase from standard GAs and GBs to the real existing bulk phases [4].

Furthermore we present the rCCC (relaxed COSMO cluster-continuum) model [5], a quantum chemical solvation model for the calculation of Gibbs solvation energies of the proton with good accuracy. The rCCC values can be used to anchor individual pH scales in different solvents to our universal scale.

Authors’ Affiliations

Institute for Inorganic and Analytical Chemistry, Freiburger Materialforschungszentrum FMF and Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-Universität Freiburg, Freiburg, 79104, Germany
Institute of Chemistry, University of Tartu, Tartu, 50411, Estonia


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  4. Himmel D, Goll SK, Leito I, Krossing I: . to be publishedGoogle Scholar
  5. Himmel D, Goll SK, Leito I, Krossing I: Anchor points for the unified Brønsted acidity scale: The rCCC model for the calculation of standard Gibbs energies of proton solvation in eleven representative liquid media. Chem Eur J. 2011, 17: 5808-5826. 10.1002/chem.201003164.View ArticleGoogle Scholar


© Goll et al; licensee BioMed Central Ltd. 2012

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.