C6H,008 or HO 2 C[CH
OH] 4 CO 2 H, in chemistry, a tetraoxydicarboxylic acid which exists in three stereoisomeric forms. The ordinary or dextro (d)-saccharic acid is formed in the oxidation of cane sugar, grape sugar, d-gluconic acid and many other carbohydrates with nitric acid. It forms a deliquescent mass. On standing, the syrupy acid gives the crystalline lactonic acid, C 6 H 8 0 7. Sodium amalgam reduces it to glucuronic acid, C 5 H 10 0 7 or OHC[CH
OH] 4 CO 2 H, whilst hydriodic acid reduces it to adipic acid, HO 2 C[CH 2 ] 4 CO 2 H. Nitric acid oxidizes it to dextro-tartaric acid and oxalic acid. Laevo (1)- saccharic acid is formed by oxidizing Z-gluconic acid with nitric acid, whilst the inactive (d+l)-acid is obtained similarly from inactive gluconic acid. These acids closely resemble the d acid except in their action on polarized light. For their relations XXIII. 31 a to the glucoses see Sugar. Mucic acid is isomeric with these acids.