Unlike her siblings (Nitriles) and other Cyanides, Acetonitrile is a very calm and tolerant person. Hydrogen Cyanide hates her and excludes her at any chance. To him, Acetonitrile had failed to be a Nitrile by not conforming to the "highly toxic" standards.
Acetonitrile has short brown curly hair and blue eyes. She has dark skin like her siblings. Acetonitrile looks very much like her younger sister Acrylonitrile.
Acetonitrile worked in Acetone's nail salon until 2000. Acetone accepted her as an employee despite Ethyl Acetate's warnings about Acetonitrile being a cyanide and that it was an immutable fact of her nature. Acetone believed that, as a nitrile, Acetonitrile was different from cyanides out of her love for Acetonitrile.
After the death of a human in 1999, Acetonitrile was blamed by Acetone for the murder in March 2000. She was forced to quit her job as a result, later Acetonitrile tried working in a pharmacy and a battery factory.