Paraformaldehyde vs. Formaldehyde — What's the Difference?

Paraformaldehyde (PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8–100 units. Paraformaldehyde commonly has a slight odor of formaldehyde due to decomposition.

Formaldehyde ( (listen) fer-mal-duh-hahyd, also (listen) for-) (systematic name methanal) is a naturally occurring organic compound with the formula CH2O (H−CHO). The pure compound is a pungent-smelling colorless gas that polymerises spontaneously into paraformaldehyde (refer to section Forms below), hence it is stored as an aqueous solution (formalin).

A white solid oligomer of formaldehyde, (CH2O)n, where n is at least 6, used as a disinfectant, fumigant, and fungicide.

A pungent colorless flammable gaseous compound, CH2O, the simplest and most reactive aldehyde, used for manufacturing melamine and phenolic resins, fertilizers, dyes, and embalming fluids and in aqueous solution as a preservative and disinfectant.

(organic compound) A solid oligomer of formaldehyde that is used as a fumigant, and as a fixative in histology

(organic compound) The simplest aldehyde, HCHO, a colourless gas that has many industrial applications; it dissolves in water to give formol (10%) and formalin.

A polymer of formaldehyde obtained as a white crystalline substance by concentration of a formaldehyde solution. Formula (CH20)n. It dissolves in hot water with the release of formaldehyde, and is used as a disinfectant.

A colorless, volatile liquid, H2CO, resembling acetic or ethyl aldehyde, and chemically intermediate between methyl alcohol and formic acid.

A colorless poisonous gas; made by the oxidation of methanol