Acetylenedicarboxylic acid
Compounds
Acetylenedicarboxylic acid or butynedioic acid is an organic compound with the formula H₂C₄O₄ or HO−C−C≡C−C−OH. It is a crystalline solid that is soluble in diethyl ether. Wikipedia
Formula: C4H2O4
Molar mass: 114.06 g/mol
Melting point: 175 to 176 °C (347 to 349 °F; 448 to 449 K) (decomposes); 180–187 °C (decomposes)