An aminoacetophenone is a compound formed by the substitution of an amine group for one of the hydrogens of acetophenone, with the molecular formula C8H9NO, or a specific isomer of this compound.
The formula is C2N2H4, but showing the order of the atoms in the molecule, it is
H2N-CH2-CN
(with a triple bond between the right-most C and N, and all others single bonds)
An acetonitrile is the simplest organic cyanide or nitrile, chemical formula CH3CN.