paraformaldehyde vs. formaldehyde

a white, crystalline polymer of formaldehyde, (HCOH) n , from which it is obtained by evaporation of the aqueous solution: used chiefly as an antiseptic.

a colorless, toxic, potentially carcinogenic, water-soluble gas, CH 2 O, having a suffocating odor, usually derived from methyl alcohol by oxidation: used chiefly in aqueous solution, as a disinfectant and preservative, and in the manufacture of various resins and plastics.