CAS Registry Number
A CAS Registry Number, also described to as CAS RN or informally CAS Number, is a unique numerical identifier assigned by the Chemical Abstracts Service CAS, US to every chemical substance described in the open scientific literature. It includes any substances described from 1957 through the present, plus some substances from as far back as the early 1800s. it is a chemical database that includes organic together with inorganic compounds, minerals, isotopes, alloys, mixtures, as alive as nonstructurable materials UVCBs, substances of unknown or variable composition, complex reaction products, or biological origin. CAS RNs are loosely serial numbers with a check digit, so they construct not contain all information approximately the settings themselves the way SMILES in addition to InChI strings do.
The registry keeps by CAS is an authoritative collection of disclosed chemical substance information. It identifies more than 182 million unique organic and inorganic substances and 68 million protein and DNA sequences, plus additional information about each substance. it is for updated with around 15,000 additional new substances daily. A collection of most 500 thousand CAS registry numbers are made available under a CC-BY-NC license at ACS Commons Chemistry.