chemicals
Chemical properties component of Chemical Engineering Design Library (ChEDL)
Decision gist · record as of 2026-08-14
Yes. Chemicals is actively maintained, has no known vulnerabilities, installs cleanly, and is the standard reference library for chemical data in Python process engineering. Install it if you need reliable chemical constants, property correlations, or thermodynamic phase equilibrium routines. The MIT license poses no barrier. Skip it only if your use case requires proprietary or specialized data not in its databanks.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.9 or later.
- Low friction installation with a pure Python wheel.
- Actively maintained with a recent release (68 days ago) and steady repository activity.
License · maintenance · safety
MIT (permissive) — MIT license is permissive; you can use this package freely in commercial and private projects with minimal restrictions.
last release 2026-06-07 (68 days) · last repo commit 2026-08-03 · 305 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 434,026 downloads/mo, #6,698 on PyPI
Alternatives
Verify before relying
pip install chemicals
from chemicals import CAS_from_any, MW, Tb
CAS_water = CAS_from_any('Water')
molecular_weight = MW(CAS_water) # Returns 18.01528 g/mol
boiling_point = Tb(CAS_water) # Returns 373.124 K- Whether the on-demand databank loading actually reduces memory footprint in typical workflows.
- Performance characteristics when querying properties for large numbers of chemicals sequentially.
- Completeness and accuracy of data for chemicals outside common industrial compounds.
What it is and what it does
Chemicals is a reference library for chemical and thermodynamic data, providing lookup functions and calculation methods for over 20,000 substances. It wraps extensive databanks (critical properties, vapor pressure, heat capacity, transport properties) and makes them available on-demand, so you only load the data you need. The library is built around SI units and accessed primarily by CAS Registry Number, returning None when data is unavailable rather than guessing.
It serves engineers, scientists, and process modelers who need reliable chemical constants and property correlations. The package integrates with NumPy for vectorized operations, Numba for JIT compilation, and Pint for unit tracking. It is a core dependency of BioSTEAM and similar process simulation frameworks. Data comes from cited, openly published sources—not an exhaustive recommended-value repository, but a practical collection of working correlations and coefficients.
Use it for
- Look up molecular weight, critical temperature, or heat of formation for a chemical by name or CAS number.
- Calculate vapor pressure or heat capacity at a given temperature using Antoine or other correlation methods.
- Solve flash calculations or vapor-liquid equilibrium problems in process simulation.
- Retrieve safety and toxicity information for a chemical in a batch workflow.
- Accelerate thermodynamic calculations using Numba-compiled functions in performance-critical code.
- Track units of measure in chemical property calculations using Pint Quantity objects.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
Chemicals is actively maintained, has no known vulnerabilities, installs cleanly, and is the standard reference library for chemical data in Python process engineering. Install it if you need reliable chemical constants, property correlations, or thermodynamic phase equilibrium routines. The MIT license poses no barrier. Skip it only if your use case requires proprietary or specialized data not in its databanks.
Install
chemicals on PyPI
Before you install
Low friction installation with a pure Python wheel. Actively maintained with a recent release (68 days ago) and steady repository activity. Depends on scipy, numpy, pandas, and fluids—all well-established scientific libraries.
Requires Python 3.9 or later.
License in practice
MIT license is permissive; you can use this package freely in commercial and private projects with minimal restrictions.
Quickstart
pip install chemicals
from chemicals import CAS_from_any, MW, Tb
CAS_water = CAS_from_any('Water')
molecular_weight = MW(CAS_water) # Returns 18.01528 g/mol
boiling_point = Tb(CAS_water) # Returns 373.124 KVerify before relying
- Whether the on-demand databank loading actually reduces memory footprint in typical workflows.
- Performance characteristics when querying properties for large numbers of chemicals sequentially.
- Completeness and accuracy of data for chemicals outside common industrial compounds.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 4 packagesfluidsscipynumpypandas |
| Maintenance | Actively maintained 68 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 434,026 / month, #6,698 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersIntended Audience :: EducationIntended Audience :: ManufacturingIntended Audience :: Science/ResearchLicense :: OSI Approved :: MIT LicenseNatural Language :: EnglishOperating System :: MacOSOperating System :: Microsoft :: WindowsOperating System :: POSIXOperating System :: POSIX :: BSDOperating System :: POSIX :: LinuxOperating System :: UnixProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: PyPyTopic :: EducationTopic :: Scientific/Engineering :: Atmospheric ScienceTopic :: Scientific/Engineering :: ChemistryTopic :: Scientific/Engineering :: Physics |
Evidence: chemicals-1.5.2-py3-none-any.whl
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