Ethynol (or hydroxyacetylene, ethynyl alcohol) is an alkyneâÂÂalcohol (ynol) with the formula C<sub>2</sub>H<sub>2</sub>O. It is the much-less-stable tautomer of ethenone.
At low temperature in a solid argon matrix it is possible to tautomerise ethenone to form ethynol.