Some typical and important members of this class have structures as follows: Most of the 1,2-dicarbonyl compounds are yellow. Ethanedial is unusual in being yellow in the liquid state, but green in the vapor state. It has very reactive aldehyde groups and is employed in the manufacture of plastics and as a component of embalming fluids to harden proteins by linking together their amino groups through imine formation: Ethanedial undergoes an internal Cannizzaro reaction with alkali to give hydroxyethanoic (glycolic) acid: An analogous reaction occurs with diphenylethanedione, which results in carbon-skeleton rearrangement. This is one of the few carbon-skeleton rearrangements brought about by basic reagents, and is known as the " benzilic acid rearrangement ".