mesoxalic acid mesoxalic acid mesoxalic acid, also called oxomalonic acid or ketomalonic acid, is an organic compound with formula c3h2o5 or ho−(c=o)3−oh. mesoxalic acid names preferred iupac name oxopropanedioic acid other names ketomalonic acidoxomalonic acidα-ketomalonic acid2-oxopropanedioic acid identifiers cas number 473-90-5 y 3d model (jsmol) interactive image chebi chebi:30842 y chemspider 9727 y drugbank db03589 y echa infocard 100.006.796 kegg c00830 y pubchem cid 10132 unii 62r514he48 y comptox dashboard (epa) dtxsid3021649 inchi inchi=1s/c3h2o5/c4-1(2(5)6)3(7)8/h(h,5,6)(h,7,8) ykey: xeevljkyyuvtrc-uhfffaoysa-n yinchi=1/c3h2o5/c4-1(2(5)6)3(7)8/h(h,5,6)(h,7,8)key: xeevljkyyuvtrc-uhfffaoyaw smiles o=c(o)c(=o)c(=o)o properties chemical formula c3h2o5 molar mass 118.045 g/mol except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). y verify (what is yn ?) infobox references mesoxalic acid is both a dicarboxylic acid and a ketonic acid. it readily loses two protons to yield the divalent anion c3o2−5, called mesoxalate, oxomalonate, or ketomalonate. these terms are also used for salts containing this anion, such as sodium mesoxalate, na2c3o5; and for esters containing the −c3o5− or −o−(c=o)3−o− moiety, such as diethyl mesoxalate, (c2h5)2c3o5. mesoxalate is one of the oxocarbon anions, which (like carbonate co2−3 and oxalate c2o2−4) consist solely of carbon and oxygen. mesoxalic acid readily absorbs and reacts with water to form a product commonly called "mesoxalic acid monohydrate", more properly dihydroxymalonic acid, ho−(c=o)−c(oh)2−(c=o)−oh. in product catalogs and other contexts, the terms "mesoxalic acid", "oxomalonic acid" and so on often refer to this "hydrated" compound. in particular, the product traded as "sodium mesoxalate monohydrate" is almost always sodium dihydroxymalonate. synthesis mesoxalic acid can be obtained synthetically by hydrolysis of alloxan with baryta water, by warming caffuric acid with lead acetate solution, or from glyceryl diacetate and concentrated nitric acid in the cold. the product can be obtained also by oxidation of tartronic acid or glycerol. since they are carried out in water, these procedures generally give the dihydroxy derivative. it is also prepared by the oxidation of glycerol with the help of bismuth(iii) nitrate.