This site is an OpenSource resource for Chemical Markup Language - both the definitions, the tools needed to process it, and lots of examples.
CML (Chemical Markup Language) is a new approach to managing molecular information. It has an extensible scope as it covers disciplines from macromolecular sequences to inorganic molecules and quantum chemistry. CML is new in bringing the power of XML to the management of chemical information. In simple terms it is "HTML for Molecules", but there is a great deal more to it than that. CML and associated tools allows for the conversion of current files without semantic loss into structured documents, including chemical publications, and provides for the precise location of information within files.
CML has been designed carefully so that it is as easy as possible for the 'average chemist' to understand it. Like a lot of chemistry it's not trivial, but it's no harder than Cahn-Ingold-Prelog chirality rules, and easier than Huckel theory. It helps if you know something about HTML (the hypertext language of the WWW) and have tried to transfer data files between sites or programs. It's not magic, and doesn't do anything that isn't really just common sense, but it hides a lot of the inconvenience that we have at present.