chemicals: Chemical properties component of Chemical Engineering Design Library (ChEDL)

Key Features & Capabilities

The chemicals library features an extensive compilation of pure component chemical data that can serve engineers, scientists, technicians, and anyone working with chemicals. The chemicals library facilitates the retrieval and calculation of:

  • Chemical constants including formula, molecular weight, normal boiling and melting points, triple point, heat of formation, absolute entropy of formation, heat of fusion, similarity variable, dipole moment, acentric factor, etc.

  • Assorted information of safety and toxicity of chemicals.

  • Methods (and their respective coefficients) for the calculation of temperature and pressure dependent chemical properties including vapor pressure, heat capacity, molar volume, thermal conductivity, surface tension, dynamic viscosity, heat of vaporization, relative permittivity, etc.

  • Methods to solve thermodynamic phase equilibrium, including flash routines, vapor-liquid equilibrium constant correlations, and both numerical and analytical solutions for the Rachford Rice and Li-Johns-Ahmadi equations. Rachford Rice solutions for systems of 3 or more phases are also available.

Data for over 20,000 chemicals are made available as local databanks in this library. All databanks are loaded on-demand, saving loading time and RAM. For example, if only data on the normal boiling point is required, the chemicals library will only load normal boiling point datasets. This on-demand loading feature makes the chemicals library an attractive dependence for software modeling chemical processes. In fact, The Biorefinery Simulation and Techno-Economic Analysis Modules (BioSTEAM) is reliant on the chemicals library for the simulation of unit operations.

The chemicals library also supports integration with Numba, a powerful accelerator that works well with NumPy; Pint Quantity objects to keep track of units of measure; and NumPy vectorized functions.

If you need to know something about a chemical, give chemicals a try.



Get the latest version of chemicals from

If you have an installation of Python with pip, simple install it with:

$ pip install chemicals

If you are using conda, you can install chemicals from conda-forge channel:

$ conda install -c conda-forge chemicals

To get the git version, run:

$ git clone git://

Latest source code

The latest development version of chemicals’s sources can be obtained at

Bug reports

To report bugs, please use the chemicals’s Bug Tracker at:

License information

See LICENSE.txt for information on the terms & conditions for usage of this software, and a DISCLAIMER OF ALL WARRANTIES.

Although not required by the chemicals license, if it is convenient for you, please cite chemicals if used in your work. Please also consider contributing any changes you make back, and benefit the community.


To cite chemicals in publications use:

Caleb Bell, Yoel Rene Cortes-Pena, and Contributors (2016-2023). Chemicals: Chemical properties component of Chemical Engineering Design Library (ChEDL)

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