A white, amorphous, deliquescent powder, (CO.H)2, obtained by the partial oxidation of glycol. It is a double aldehyde, between glycol and oxalic acid.

Glyoxal is an organic compound. This compound is the smallest aliphatic di-aldehyde just like methylglyoxal is the smallest ketoaldehyde. Glyoxal is commercially available as a solution in water (40%) or as a hydrate.