Microwave Spectra of 13C- and 18O-Containing Species and the Structure of Vinylene Carbonate

The microwave spectra of two ¹³C and two ¹⁸O species of vinylene carbonate have been analyzed. The spectra were observed with the isotopes present in natural abundance. An $r_s$ structure of the heavy atoms in the molecule shows a short C=O bond length of 1.1908 ± 0.0006 Å with the other bonds being of approximately the expected length. The ring angles are nearly equal with two bonds at the carbon atoms making angles of 108°40′ ± 9′ and 108°40′ ± 40′ and the angle at the oxygen atom being 106°56′ ± 24′.