Table of Functional Group Priorities for Nomenclature

by James

in Alcohols, Aldehydes, Alkanes, Alkenes, Alkyl Halides, Alkynes, Carboxylic acids, Esters, Functional Groups, Ketones, Nomenclature

Because I figured I should have it on this site somewhere – although this covers most of the functional groups you’ll meet in Org1/Org2, if you run into a thioketone or some other bizarre entity, you’ll probably want to see Reusch or Wikipedia


Here are some examples of applying the order of functional group priorities to solve nomenclature problems. The highest ranked functional group becomes the suffix – it’s highlighted in red.

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{ 14 comments… read them below or add one }

abhi November 8, 2011 at 7:25 am

Animation makes it all the more interesting !


deepak December 21, 2011 at 1:34 pm



IP June 18, 2013 at 6:34 pm

I think ether should be right after amines and alkane after nitro? some other website seem to say that, which one is correct?


james June 19, 2013 at 9:11 pm

With amines, the suffix “ine” is used, but when nitro groups or ethers are present, the alkane suffix is used:


christopher unyime ebong September 25, 2013 at 10:41 am

i think alkyne should come before alkene: it should be alkyne-alkene-alkane, decreasing unsaturation and increasing saturation…


James Ashenhurst September 25, 2013 at 10:24 pm

Alkene does go first over alkyne, but I believe it is due to the alphanumeric priority of -ene over -yne and not based on the extent of saturation:


Ptachia Bar-On October 6, 2013 at 5:28 pm

If Halogens have higher perioity than Nitro why the Nitro group is written after the Bromine


James Ashenhurst October 9, 2013 at 9:33 am

It’s just due to alphabetization. For example we would number 2-bromo 3-nitro butane based on the fact that bromine is higher up in (our) alphabet than nitro.


Birupakshya Singh December 26, 2013 at 2:52 am

can anyone plz say what is d criteria for this table.????..


James Ashenhurst December 27, 2013 at 12:58 am



Birupakshya Singh January 21, 2014 at 3:02 am

well…but can u plz suggest me what r the criterias which IUPAC have applied???


James January 21, 2014 at 12:29 pm

I believe it is at least partially based on oxidation state, with higher oxidation state having higher priority. But that doesn’t explain why alkenes are higher priority than alkynes. Nomenclature is a human convention.


Rani January 11, 2014 at 1:06 pm

please give some example where carboxylic acid act as prefix .Will sulphonic acid be given more priority than carboxylic acid?


Govind Pradeep January 15, 2014 at 11:33 am

Why does alkyne have more priority ovr alkene? Because i have seen compounds where the least no: is given to alkynes ie., they hav been given most priority ovr alkene..for example, 6-chloro-4-ethyl-5-methylhept-5-en-1-yne


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