IUPAC > Gold Book > alphabetical index > L > Lippman's equation
icon

IndexesDownload


Lippman's equation

An equation which gives the electric charge per unit area of an interface (electrode):
( ∂ γ ∂ E A ) T , p , μ i ≠ μ = − Q A
where γ is the interfacial tension, E A is the potential of a cell in which the reference electrode has an interfacial equilibrium with one of the ionic components of A, Q A is the charge on unit area of the interface, μ i is the chemical potential of the combination of species i whose net charge is zero, T is the thermodynamic temperature and p is the external pressure. Since more than one type of reference electrode may be chosen, more than one quantity Q may be obtained. Consequently Q cannot be considered as equivalent to the physical charge on a particular region of the interphase. It is in fact an alternative way of expressing a surface excess or combination of surface excess of charged species.
Source:
PAC, 1974, 37, 499 (Electrochemical nomenclature) on page 508
PAC, 1986, 58, 437 (Interphases in systems of conducting phases (Recommendations 1985)) on page 445
Interactive Link Maps
First LevelSecond LevelThird Level
GraphGraphGraph
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. doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi:10.1351/goldbook.L03577.
Original PDF version: http://www.iupac.org/goldbook/L03577.pdf. The PDF version is out of date and is provided for reference purposes only. For some entries, the PDF version may be unavailable.
Current PDF version | Version for print | History of this term
picture