organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain ...

, a primary carbon is a carbon atom which is bound to only one other carbon atom. It is thus at the end of a carbon chain. In case of an

alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in whi ...

, three

hydrogen atom A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral hydrogen atom contains a single positively charged proton in the nucleus, and a single negatively charged electron bound to the nucleus by the Coulomb for ...

s are bound to a primary carbon (see propane in the figure on the right). A hydrogen atom could also be replaced by a

hydroxy group In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

(), which would make the molecule a

primary alcohol A primary alcohol is an alcohol in which the hydroxy group is bonded to a primary carbon atom. It can also be defined as a molecule containing a “–CH2OH” group. In contrast, a secondary alcohol has a formula “–CHROH” and a tertiary ...

. {, class="wikitable centered" style="text-align: center; font-size: 90%; margin-bottom: 10px;" , - , , style="background-color:#AAC1FF" , ''primary'' carbon , style="background-color:#7A91FF" , ''secondary'' carbon , style="background-color:#7A91FF" , ''tertiary'' carbon , style="background-color:#7A91FF" , ''quaternary'' carbon , - , align="center" style="background-color:#CAE1FF; height:80px; width:20%" , General structure
(R =

Organyl group In organic and organometallic chemistry, an organyl group (commonly denoted by the letter " R") is an organic substituent with one (sometimes more) free valence electron(s) at a carbon atom.. The term is often used in chemical patent literatur ...

) , style="background-color:#FFFFFF" , , style="background-color:#BFBFBF" , , style="background-color:#BFBFBF" , , style="background-color:#BFBFBF" , , - , align="center" style="background-color:#CAE1FF; height:80px; width:20%" , Partial
Structural formula , style="background-color:#FFFFFF" , , style="background-color:#BFBFBF" , , style="background-color:#BFBFBF" , , style="background-color:#BFBFBF" ,

References

Chemical nomenclature Organic chemistry