Wiktionary
acetylenediol
n. (context organic compound English) The diol of acetylene.
Wikipedia
Acetylenediol
Acetylenediol, or ethynediol, is a chemical substance with formula HO-C≡C-OH. It is the diol of acetylene. Acetylenediol is unstable in the condensed phase, although its tautomer glyoxal H(C=O)H is well known.