Exam QuestionsRevision NotesVideo TutorialsPast Papers

Nomenclature

01Nomenclature

Carbon chain names

This section covers the stems used to name carbon chains and the identification of the parent chain or ring.

Systematic organic names are based on molecular structure. The stem identifies the number of carbon atoms in the parent carbon chain.

Carbon atoms Stem Straight-chain alkane Molecular formula
1meth-methaneCHX4\ce{CH4}
2eth-ethaneCX2HX6\ce{C2H6}
3prop-propaneCX3HX8\ce{C3H8}
4but-butaneCX4HX10\ce{C4H10}
5pent-pentaneCX5HX12\ce{C5H12}
6hex-hexaneCX6HX14\ce{C6H14}

Choosing the parent

For a branched compound, identify the longest continuous carbon chain. Its number of carbon atoms determines the parent stem.

Straight chain

Six carbon atoms in one continuous chain give the parent name hexane.

Ring

A saturated six-carbon ring is cyclohexane; cyclo- identifies the ring.

Aliphatic compounds may contain an open straight or branched carbon chain, or a non-aromatic carbon ring. A benzene ring is not present in an aliphatic compound.

Systematic naming is required here for chains and rings containing up to six carbon atoms each.

Create a free account to continue

Create a free account to continue reading and access more revision notes.