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When I name an organic compound, I follow a preferential order like so: http://www.masterorganicchemistry.com/2011/02/14/table-of-functional-group-priorities-for-nomenclature/ But I don't understand why this order exists. And intuitively (to me at least), a triple bond has a higher preference than a double bond... then why is the order like in the link, i.e., double bond preferred over triple bond? Is there any chemistry behind this?

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  • $\begingroup$ Please note that the so-called “Table of Functional Group Priorities For Nomenclature” shown on masterorganicchemistry.com tries to combine the seniority order of suffixes with prefixes and endings. This can be misleading and result in wrong names. In particular, there is no suffix ‘-ane’, ‘-ene’ or ‘-yne’ (these are endings), and multiple bonds (and all groups that follow in that table) are actually not considered in the seniority order. Please do not use such sources. $\endgroup$ – Loong Apr 26 '18 at 17:11
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The naming of organic compounds are governed by IUPAC guidelines, specifically the way the names are formed are by some general principles, which are given on the IUPAC website at their page Guide to Name Construction: General Principles, with naming examples here.

Another rather nice summary is found on the webpage Nomenclature (Reusch, 1999), states that a organic compound name will have the following features, based on several common chemical characteristics of organic compounds:

• A root or base indicating a major chain or ring of carbon atoms found in the molecular structure.

• A suffix or other element(s) designating functional groups that may be present in the compound.

• Names of substituent groups, other than hydrogen, that complete the molecular structure.

(Specific IUPAC guidelines for different hydrocarbons are included in the link).

Another summary is found on the handout Short Summary of IUPAC Nomenclature of Organic Compounds (Dr. Jan Simek, California Polytechnic State University at San Luis Obispo), which state that the general nomenclature principle is:

IUPAC nomenclature is based on naming a molecule’s longest chain of carbons connected by single bonds, whether in a continuous chain or in a ring. All deviations, either multiple bonds or atoms other than carbon and hydrogen, are indicated by prefixes or suffixes according to a specific set of priorities.

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  • $\begingroup$ But this prioritization is more of a standardisation than whether the branch has any chemical properties that lead to an order as determined by IUPAC. $\endgroup$ – Artemisia Dec 28 '13 at 8:27
  • $\begingroup$ @Artemisia, the 1st quote is the chemical reasons for the prioritisation determined by IUPAC. $\endgroup$ – user3901 Dec 28 '13 at 8:30

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