C9H18O

The molecular formula C9H18O (molar mass: 142.24 g/mol) may refer to:


 * Nonanal
 * Nonanones
 * 2-Nonanone
 * 3-Nonanone
 * 4-Nonanone
 * 5-Nonanone, or dibutyl ketone
 * 3,3,5-Trimethylcyclohexanol