Knowledge Bank

The infrared spectra of ethylene carbonate $(CH2-O-CO-O-CH2$ in the solid, liquid and vapor states and its solutions in water, chloroform, benzene, carbon tetracloride and carbon disulfide have been studied between 3600 and $400cm-1$, together with the Raman spectrum in aqueous solution. Previous X-ray crystal structure $determination1$ has shown that the five-membered ring of the ethylene carbonate molecule is not planar and has symmetry $C2$ in the crystal. Evidence will be presented from the spectroscopic work that the symmetry of the molecule changes from $C2$ in the solid state to $C2v$ in the other states and that the five-membered ring becomes planat. An assignment of all the observed absorption bands will be given in terms of the fundamental vibrations of the molecule.