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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
The systematic name of pyridine, within the Hantzsch–Widman nomenclature recommended by the IUPAC, is azinine. However, systematic names for simple compounds are used very rarely; instead, heterocyclic nomenclature follows historically established common names. IUPAC discourages the use of azinine/azine in favor of pyridine. [128]
Phase behavior Triple point: 231.48 K (–41.67 °C), ? Pa Critical point: 619 K (346 °C), 5660 Pa Std enthalpy change of fusion, Δ fus H o: 8.28 kJ/mol Std entropy change
Containing a pyridinium ion, pyridinium chloride has a pK a of approximately 5, slightly more acidic than that of typical amines.This is due to the hybridization of the nitrogen: the nitrogen is sp 2 hybridized and more electronegative than those nitrogens in ammonium cations, which are sp 3 hybridized.
Although pyridine is an excellent source of carbon, nitrogen, and energy for certain microorganisms, introduction of a halogen moiety significantly retards degradation of the pyridine ring. With the exception of 4-chloropyridine, each of the mono- and di-substituted chloropyridines were found to be relatively resistant to microbiological ...
It is the conjugate acid of pyridine. Many related cations are known involving substituted pyridines, e.g. picolines, lutidines, collidines. They are prepared by treating pyridine with acids. [3] As pyridine is often used as an organic base in chemical reactions, pyridinium salts are produced in many acid-base reactions.
The name breaks down as: cetyl- refers to the cetyl group, named for its relation to cetyl alcohol, which was first isolated from whale oil (Latin: cetus); [7] pyridinium refers to the cation [C 5 H 5 NH] +, the conjugate acid of pyridine; chloride refers to the anion Cl −.
C 5 H 5 N + HCl + CrO 3 → [C 5 H 5 NH][CrO 3 Cl] In one alternative method, formation of toxic chromyl chloride (CrO 2 Cl 2) fumes during the making of the aforementioned solution were minimized by simply changing the order of addition: a cold solution of pyridine in concentrated hydrochloric acid was added to solid chromium trioxide under ...