The ease of distortion of the electron cloud of a
molecular entity by an electric field (such as that due to the proximity of a charged
reagent). It is experimentally measured as the ratio of induced
dipole moment(
) to the field
which induces it:
The units of
are
.
In ordinary usage the term refers to the '
mean polarizability', i.e., the average over three rectilinear axes of the molecule. Polarizabilities
in different directions (e.g. along the bond in
Cl2
,
called '
longitudinal polarizability', and in the direction perpendicular to the bond, called '
transverse polarizability') can be distinguished, at least in principle. Polarizability along the bond joining
a substituent to the rest of the molecule is seen in certain modern theoretical approaches
as a factor influencing chemical reactivity, etc., and parametrization thereof has
been proposed.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1151
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.
