· Name (problem because there are multiple names for one chemical)
· Formula (problem because there is one formula for multiple chemicals)
· Structure (sometimes search tools will not allow you to deal with stereochemistry)
· Mass (problem because there is one mass for multiple chemicals)
· Physical Properties (problem because there are similar physical properties for multiple chemicals)
· Spectra (difficult to search using any source but is like a Photo ID for a chemical)
· Unique Identifier (i.e. an equivalent of a Social Security Number for a chemical): (1) IUPAC (International Union of Pure and Applied Chemistry) Identifier or (2) CAS (Chemical Abstracts Service) Registry Number