Acraldehyde

Chem. [f. L. acr-is, acrid + ALDEHYDE.] One of the polymeric modifications of ALDEHYDE.

1869.  Roscoe, Elem. Chem., 350. Aldehyde is capable of existing in three other peculiar states … a third modification termed Acraldehyde boils at 110°. The molecular formula appears to be C₄H₈O₂ or 2(C₂H₄O).