1. Basic Identification Information

Parameter	English Specification/Value
IUPAC Name	2-Oxoacetic acid (also: Oxoethanoic acid)
Common Name(s)	Glyoxylic acid; Oxoacetic acid; Formylformic acid; Glyoxalic acid; Acetic acid, 2-oxo-
CAS Registry Number	298-12-4 (anhydrous); 79-14-1 (monohydrate, most commercially available form)
EC/EINECS Number	206-058-5 (anhydrous); 201-180-5 (monohydrate)
Molecular Formula	C₂H₂O₃ (anhydrous); C₂H₄O₄ (monohydrate)
Molecular Weight	74.04 g/mol (anhydrous); 92.05 g/mol (monohydrate)
Chemical Class	α-Keto acid; aldehyde-carboxylic acid derivative; keratolytic agent; synthetic intermediate
Related Compound	Glycolic acid (CAS 79-14-1) (monohydroxyacetic acid, no aldehyde group; milder exfoliant for cosmetics); Oxalic acid (CAS 144-62-7) (dicarboxylic acid, no ketone/aldehyde groups; stronger chelator)

2. Physicochemical Properties

Property Category	Specific Parameter	Specification/Value
Structural Features	Functional Groups	Aldehyde group (-CHO) at C1; carboxyl group (-COOH) at C2 (dual functionality enables both reduction/oxidation and acid-base reactions; prone to intramolecular hydrogen bonding)
Physical Appearance	State & Color	Anhydrous form: white crystalline powder (decomposes readily); commercial form: 40–50% aqueous solution (colorless to pale yellow clear liquid); faint pungent odor
	Melting Point	98–100 °C (monohydrate, lit.); anhydrous form decomposes at ≈70 °C (sublimes under vacuum)
	Boiling Point	Decomposes before boiling (aqueous solution boils at 100–105 °C with partial polymerization)
	Density (25 °C)	1.30 g/cm³ (50% aqueous solution); 1.49 g/cm³ (anhydrous crystalline form)