Oxalic acid Oxalic acid Oxalic acid is an organic compound with the formula CHO. It is a colorless crystalline solid that forms a colorless solution in water. Its condensed formula is HOOCCOOH, reflecting its classification as the simplest dicarboxylic acid. Its acid strength is much greater than that of acetic acid. Oxalic acid is a reducing agent and its conjugate base, known as oxalate (), is a chelating agent for metal cations. Typically, oxalic acid occurs as the dihydrate with the formula CHO·2HO. It occurs naturally in many foods, but excessive ingestion of oxalic acid or prolonged skin contact can be dangerous.
Cinnamic acid resulting in different linear free energy relationships. Cinnamic acid Cinnamic acid is an organic compound with the formula CHCH=CHCOOH. It is a white crystalline compound that is slightly soluble in water, and freely soluble in many organic solvents. Classified as an unsaturated carboxylic acid, it occurs naturally in a number of plants. It exists as both a "cis" and a "trans" isomer, although the latter is more common. Cinnamic acid is a central intermediate in the biosynthesis of myriad natural products include lignols (precursors to lignin and lignocellulose), flavonoids, isoflavonoids, coumarins, aurones, stilbenes, catechin, and phenylpropanoids. Its biosynthesis is performed