Formyl cyanide is a simple organic compound with the formula HCOCN and structure . It is simultaneously a nitrile () and an aldehyde (). Formyl cyanide is the simplest member of the acyl cyanide family. It is known to occur in space in the Sgr B2 molecular cloud.
Formyl cyanide was first made through methoxyacetonitrile flash vacuum pyrolysis at 600 ðC. The same technique with cinnamyloxyacetonitrile or allyloxyacetonitrile also generates formyl cyanide.
In molecular clouds, formation of formyl cyanide is speculated to result from formaldehyde and the cyanide radical:
In Earth's atmosphere, the pollutant acrylonitrile reacts with hydroxyl radical forming formyl cyanide, hydroperoxyl and formaldehyde:
Formyl cyanide reacts rapidly with trace quantities of water to form formic acid and hydrogen cyanide.
By formally substituting the hydrogen atom, cyanoformyl chloride, ClC(O)CN, and cyanoformyl bromide, BrC(O)CN are obtained.