C2H2O Index of chemical compounds with the same molecular formula From Wikipedia, the free encyclopedia The molecular formula C2H2O (molar mass: 42.04 g/mol, exact mass: 42.0106 u) may refer to: Ethenone, or ketene Ethynol, or hydroxylacetylene Oxirene This set index page lists chemical structure articles associated with the same molecular formula.If an internal link led you here, you may wish to change the link to point directly to the intended article. More information Related molecular formulas ... Related molecular formulas C2H4O CO C2H2O C3H4O C2O C2H2 C2H2O2 Close Related Articles