An organic compound, the lowest in the chain of the aliphatic aldehydes, used in large amounts in a variety of chemical manufacturing processes. It is produced principally by the vapour-phase oxidation of methanol. Large quantities of formaldehyde are used in the manufacture of phenol-, urea- and melamine-formaldehyde resins, or formaldehyde polymers (acetal-resins), and polyurethane plastics.