The reversible work of formation of unit area of new surface by cleavage. It has previously
been called specific
surface work, surface energy, surface tension or surface
free energy. The symbol recommended is

in preference to

because of the confusion with
surface charge density. The superficial work

is a scalar quantity and consequently is
isotropic.
Source:
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.