when there are large energy gaps between excited states. An example is azulene: the classical explanation is that the S1 and S2 states lie sufficiently
is a list of common chemical compounds with chemical formulae and CAS numbers, indexed by formula. This complements alternative listing at list of inorganic
compounds then were graded against these two standards and assigned octane numbers. In common with all hydrocarbons, 2,2,4-trimethylpentane is flammable.
'locants' in the case of multiple triple bonds. Locants are chosen so that the numbers are low as possible. "-yne" is also used as a suffix to name substituent