Modular Chemical Descriptor Language (MCDL): composition, connectivity, and supplementary modules.

The Modular Chemical Descriptor Language (MCDL) was developed to address the need for linear representation of structural and other chemical information for chemical databases, E-journals, and the Internet. The current paper describes in detail two major modules of the language: the composition and connectivity modules, which provide a representation of chemical structure. These modules are created using simple hierarchical principles based on ASCII codes and are unique except for stereoisomers and a few special cases (e.g., valence isomers, knot-type compounds). The MCDL also provides for additional information (such as atom coordinates, bond orders, spectra, and physical-chemical characteristics) to be included as a set of supplementary modules.