A Chemical structure in a patent may span from a defined exact structure, a family of structures to a Markush structure. A markush structure includes several possible variations at various positions of the chemical structure, in turn claiming several specific chemical compounds with closely related properties and often bioequivalence.

A chemical formulation includes multiple chemical compounds. Every single chemical compound can be available in patents and literature in a number of ways such as a chemical structure, a CAS Registry number, IUPAC name, a brand name, or is available in form of a common name used in industry.