Series of esters with two to six nitrate (NO3) groups per molecule, made by the action of concentrated nitric acid on cellulose (for example, cotton waste) in the presence of concentrated sulfuric acid. Those with five or more nitrate groups are explosive (gun cotton), but those with less were once used in lacquers, rayon, and plastics, such as colored and photographic film, until replaced by nonflammable cellulose acetate.