Henry's Law Constants (Solubilities)
Table of contents
Calculations in atmospheric chemistry depend strongly on the
availability of kinetic and thermodynamic data. For gas-phase chemistry,
evaluations such as the IUPAC
or JPL data sets greatly
facilitate obtaining reliable values. However, there has been no such
comprehensive compilation for Henry's law constants (solubilities) for
tropospheric modeling of clouds and aerosol particles. Waste water
treatment is another research area where Henry's law constants are
needed since solubility affects volatilization of toxic compounds into
the air. I have gathered data from different sources. The Henry's law
constants, which can (unfortunately) be defined in several ways and
expressed using different units, have been converted into a uniform
format (unit: mol m-3 Pa-1).
The current version (582 pages) is available here:
Compilation of Henry's law constants (version 4.0) for water as solvent
Atmos. Chem. Phys., 15, 4399-4981, 2015
If you would like to order a printed copy of the article, please contact
the Copernicus publisher at
Older (obsolete) versions are also still available:
What kind of data is included in the list?
The list contains Henry's law constants for several organic and inorganic
species in water. The Henry's law constant is defined here as the ratio of the
aqueous-phase concentration of a chemical to its equilibrium partial pressure
in the gas phase.
What kind of data is NOT included in the list?
Henry's law refers to small concentrations (lim c-->0). Maximum solubilities
are not included. Solubility products, i.e. products of ion concentrations are
not included either.
Henry's law constants for solvents other than water are not included.
Values obtained under high pressures (p >> 1000 hPa) and
temperatures (T > 373 K) are not included.
Why are CO and CO2 apparently not included?
You cannot find them in the inorganic section. CO and CO2 are
included in the miscellaneous organics subsection (all species
containing carbon atoms are in the organic section).
Can you help me? I've got a question!
You're welcome to send me an email but please don't be too disappointed in case
I don't have the time to answer it. Collecting Henry's law constants is not my
main job. It's just something I did because I needed (and still need) them for
my research. I have received much more email than I expected and I won't be
able to answer all questions individually. Before sending me an email, please
consider the following points:
Converting between different definitions and units for Henry's law constants
can be quite tricky. I'm afraid I won't have the time to answer individual
questions on how to convert from unit xxx to unit yyy.
Henry's law constants are used in several research areas, e.g. pesticide
control, waste water management, and atmospheric chemistry. Since I'm an
atmospheric chemist myself, I don't think I will be able to help you with
problems in the other research areas.
Pressure or fugacity?
The official IUPAC definition of Henry's law constants uses fugacity to
describe the gas-phase composition. In my compilation, I use pressure.
In other words, I am assuming a fugacity coefficient of 1. This
simplification is justified in environmental science where pressure is
around 1 atmosphere. As mentioned above, values obtained under high
pressures are not included in my list.
Well, I knew it would happen... A big list like this just couldn't be perfect.
I have now added a list of errors that I have made in my compilation.
Errata for version 4.0
If you notice that any Henry's law data (e.g., from your work) are
missing or incorrectly listed, please send an email
Errata for version 3.99
- Bug fix for data in table 5 by Pfeifer et al. (2001).
- The CASRN for tribromomethanol is [5405-30-1].
Errata for version 3
If you find errors in the list or if you know of additional references
that I could include, please send me an email
Especially when you have published measurements of Henry's law's
constants, I would appreciate it very much if you send me a reprint! If
you have any other comments or questions, please read the 'frequently
asked questions' first (see above)!!!
- In note 20, the solubility for strong acids should be defind
kH = ([H+] * [A-]) / p(HA)
kH = ([H+] + [A-]) / p(HA)
Thanks to J. C. Wheeler for pointing this out to me.
- There's a nasty little error in the sign
of the temperature dependence in all tables:
The values given in the third column are
d ln kH / d (1/T)
- d ln kH / d (1/T)
The solubility decreases with increasing temperature, of course. This is
shown correctly in equation (5) on page 3.
- Although not mentioned in the table, it should be noted that values
for HCHO refer to effective Henry's law constants that take into account
increased solubility due to the formation of the diol:
HCHO + H2O = CH2(OH)2
- Data from Allen et al. (1998) are measured, not estimated.
- The reference Gmehling et al. (1981) should be: J. Gmehling and U. Onken
and W. Arlt. Vapor-Liquid Equilibrium Data Collection. D. Behrens and R.
Eckermann (eds.). Dechema, Frankfurt/Main Vol. 1a (1981)
- page 15: The value of 1.3E-1 M/atm for 2-methylpentane from
Ashworth et al. (1988) was quoted incorrectly by Staudinger and Roberts
- page 36: The values listed for benzo[a]fluoranthene actually refere
- page 38: The CASRN for 1-heptanol is [111-70-6], not [110-70-6].
- page 41: The value for 1,2-ethanediol from Bone et al. (1983)
should be 4.1E5 M/atm, not 4.0E6 M/atm.
- page 44: The CASRN for methanal (formaldehyde) is [50-00-0], not
- page 60: For 2,2-dimethylpyridine, the temperature dependence is
7000 K, not 700 K.
- page 61: For 2-butyl nitrate, both the trivial name "isobutyl
nitrate" and the CASRN are wrong. The correct CASRN for 2-butyl nitrate
- page 61: The species called tert-butyl nitrate should actually be
- page 75: The value of 2.2 by Hine and Mookerjee (1975) refers to
1,1,1,2-tetrachloroethane, not to 1,1,2,2-tetrachloroethane.
- page 90: The CASRN for 1-butanethiol is [109-79-5], not [109-75-5].
- page 90: The value of 5.8E-1 by Yaws and Yang (1982) refers to
diethyl sulfide, not to diethyl disulfide.
- page 92: The species called 3,4'-PCB is actually 3,4-PCB.
- page 93: The value of 1.4E2 by USEPA (1982) refers to
2,4,6-trichlorophenol, not to 2,4,6-PCB.
This document was last changed
10 Aug 2015