This term applies in a general way to any multiparametric extension of the
Hammett equation. It is sometimes used specifically for a form of
dual substituent-parameter equation in which the actual value of the correlated property
under the influence of the substituent X is used, rather than the value relative to
that for
X
=
H.
An intercept term
corresponding to the value of
for
X
=
H
is introduced, e.g.
The equation may be applied to systems for which the inclusion of further terms to
represent other effects, e.g. steric, is appropriate.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1114
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
