Reference—Structural, displayed and skeletal formula conventions

Structural formulae show connectivity, displayed formulae show bonds, skeletal formulae show the carbon framework, and partial-skeletal forms combine conventions. Use enough bonds and labels to make one structure unambiguous.

Show heteroatoms and their attached hydrogens, indicate multiple bonds and use the accepted benzene-ring convention. A condensed formula must still distinguish functional-group position and branching.

CH₃CH(OH)CH₃ identifies propan-2-ol; a skeletal chain with –OH at the middle carbon conveys the same connectivity.

Leaving out a carbon-bound hydrogen is normal in skeletal notation, but leaving out a heteroatom or bond needed to distinguish isomers is not.