Dipole Moment (chemicals.dipole)

This module contains lookup functions for the property dipole moment.

For reporting bugs, adding feature requests, or submitting pull requests, please use the GitHub issue tracker.

Lookup Functions

chemicals.dipole.dipole_moment(CASRN, method=None)[source]

This function handles the retrieval of a chemical’s dipole moment. Lookup is based on CASRNs. Will automatically select a data source to use if no method is provided; returns None if the data is not available.

Preferred source is ‘CCCBDB’. Considerable variation in reported data has found.




Dipole moment, [debye]

Other Parameters
methodstr, optional

The method name to use. Accepted methods are ‘CCCBDB’, ‘MULLER’, or ‘POLING’, ‘PSI4_2022A’. All valid values are also held in the list dipole_all_methods.


A total of three sources are available for this function. They are:

  • ‘CCCBDB’, a series of critically evaluated data for compounds in [1], intended for use in predictive modeling.

  • ‘MULLER’, a collection of data in a group-contribution scheme in [2].

  • ‘POLING’, in the appendix in [3].

  • ‘PSI4_2022A’, values computed using the Psi4 version 1.3.2 quantum chemistry software, with initialized positions from rdkit’s EmbedMolecule method, the basis set 6-31G** and the method mp2 [4].

This function returns dipole moment in units of Debye. This is actually a non-SI unit; to convert to SI, multiply by 3.33564095198e-30 and its units will be in ampere*second^2 or equivalently and more commonly given, coulomb*second. The constant is the result of 1E-21/c, where c is the speed of light.



NIST Computational Chemistry Comparison and Benchmark Database NIST Standard Reference Database Number 101 Release 17b, September 2015, Editor: Russell D. Johnson III http://cccbdb.nist.gov/


Muller, Karsten, Liudmila Mokrushina, and Wolfgang Arlt. “Second- Order Group Contribution Method for the Determination of the Dipole Moment.” Journal of Chemical & Engineering Data 57, no. 4 (April 12, 2012): 1231-36. doi:10.1021/je2013395.


Poling, Bruce E. The Properties of Gases and Liquids. 5th edition. New York: McGraw-Hill Professional, 2000.


Turney, Justin M., Andrew C. Simmonett, Robert M. Parrish, Edward G. Hohenstein, Francesco A. Evangelista, Justin T. Fermann, Benjamin J. Mintz, et al. “Psi4: An Open-Source Ab Initio Electronic Structure Program.” WIREs Computational Molecular Science 2, no. 4 (2012): 556-65. https://doi.org/10.1002/wcms.93.


>>> dipole_moment(CASRN='64-17-5')

Return all methods available to obtain the dipole moment for the desired chemical.


CASRN, [-]


Methods which can be used to obtain the dipole moment with the given inputs.

See also

chemicals.dipole.dipole_moment_all_methods = ('CCCBDB', 'MULLER', 'POLING', 'PSI4_2022A')

Tuple of method name keys. See the dipole for the actual references