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Screenshot of the CAS Common Chemistry database with information about caffeine ().. A CAS Registry Number [1] (also referred to as CAS RN [2] or informally CAS Number) is a unique identification number, assigned by the Chemical Abstracts Service (CAS) in the US to every chemical substance described in the open scientific literature, in order to index the substance in the CAS Registry.
Chemical Abstracts Service Building B in August 2009. Columbus, Ohio. STN (Scientific & Technical Information Network) International is operated jointly [4] by CAS and FIZ Karlsruhe, and is intended primarily for information professionals, using a command language interface.
This is a list of CAS numbers by chemical formulas and chemical compounds, indexed by formula.The CAS number is a unique number applied to a specific chemical by the Chemical Abstracts Service (CAS).This list complements alternative listings to be found at list of inorganic compounds and glossary of chemical formulae
CAS Registry Number, a unique identification number, assigned by the Chemical Abstracts Service in the US to every chemical substance; Cas (mathematics)
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
The terms polymer and macromolecule do not mean the same thing. A polymer is a substance composed of macromolecules. A polymer is a substance composed of macromolecules. The latter usually have a range of molar masses (unit g mol −1 ), the distributions of which are indicated by dispersity ( Đ ).
The invariance properties of molecular descriptors can be defined as the ability of the algorithm for their calculation to give a descriptor value that is independent of the particular characteristics of the molecular representation, such as atom numbering or labeling, spatial reference frame, molecular conformations, etc. Invariance to molecular numbering or labeling is assumed as a minimal ...
IUPAC prefers the spelling icosa-for the affix corresponding to the number twenty on the grounds of etymology. However both the Chemical Abstracts Service and the Beilstein database use the alternative spelling eicosa- .