Here are some free thermodynamic databases provided in the TC TDB (Thermodynamic Data Base) format. There is no guarantee of quality or that the databases are useful for any purpose. In some databases there are references to the source of the parameters. Some databases consists of several files and may need some editing of the path to function.
If you have a database that is free and you think useful for other people please mail it to the authors. Please provide references to all parameters according to the TDB format and ensure that the database contains only public data. But do not feel dissapointed if we anyway do not put it available for any reason.
The databases here are only intended for teaching purposes. For calculations requiring high accuracy there are validated commercial databases available from many different vendors.