Open Babel

Open Babel is computer software, a chemical expert system mainly used to interconvert chemical file formats.

About
Due to the strong relationship to informatics this program belongs more to the category cheminformatics than to molecular modelling. It is available for Windows, Unix, Linux, macOS, and Android. It is free and open-source software released under a GNU General Public License (GPL) 2.0.

The project's stated goal is: "Open Babel is a community-driven scientific project assisting both users and developers as a cross-platform program and library designed to support molecular modeling, chemistry, and many related areas, including interconversion of file formats and data."

History
Open Babel and JOELib were derived from the OELib cheminformatics library. In turn, OELib was based on ideas in the original chemistry program Babel and an unreleased object-oriented programming library called OBabel.

Major features

 * chemical expert system
 * interconversion of many chemical file formats
 * substructure search, based on simplified molecular-input line-entry system (SMILES)
 * fingerprint calculation
 * 3D coordinate generation
 * wrappers for Python, Perl, Java, Ruby, C#