What does the R stand for in functional groups?

1 Answer
anor277
Feb 1, 2016

When we are not referring to optical isomerism, #R# in a formula refers to an alkyl residue, #C_nH_(2n+1)#.

Explanation:

When we write #RC(=O)H# or #RCH=CHR#, or #R_3C-X#, clearly we highlight the functional group of interest: aldehyde; olefin; halide etc. Why do we do this? Well, because the interesting chemistry is going to occur at that functional group.

The #R# substituent, of general formula #C_nH_(2n+1)# is along for the ride, and is tacked on to the end of the chain.

Related questions
See all questions in Quick Introduction of Structures
Impact of this question
5174 views around the world
You can reuse this answer
Creative Commons License