paraformaldehyde

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

A polymerized formaldehyde, (CH₂O)_n + H₂O, formed by evaporation of an aqueous solution of formaldehyde. It is an amorphous solid that dissolves gradually in water. By heating with water at 130° C. it is reconverted to formaldehyde. It is used as an antiseptic.

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 solid oligomer of formaldehyde that is used as a fumigant, and as a fixative in histology