 | |
| Names | |
|---|---|
| IUPAC name Potassium 2-hydroxy-2-oxoacetate | |
| Other names Potassium bioxalate | |
| Identifiers | |
| |
3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.004.431 |
| UNII | |
| |
| |
| Properties | |
| C2HKO4 | |
| Molar mass | 128.124 g·mol−1 |
| Appearance | White crystalline solid |
| Odor | odorless |
| Density | 2.0 g/cm3 |
| 2.5 g/100 g | |
| Solubility | slightly soluble in alcohol |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Potassium hydrogenoxalate is asalt with formula KHC2O4 or K+·HO2C-CO2−. It is one of the most common salts of thehydrogenoxalate anion, and can be obtained by reactingpotassium hydroxide withoxalic acid in 1:1 mole ratio.
The salt is also known as:potassium hydrogen oxalate,potassium bioxalate,acid potassium oxalate, ormonobasic potassium oxalate. In older literature, it was also called:Salt of sorrel,[1]sorrel salt,sel d'oseille,[2][3]sal acetosella; or,inaccurately,salt of lemon (due to the similar acidic“lemony” taste of the ediblecommon sorrel orgarden sorrel)[4]
Potassium hydrogenoxalate occurs in some plants, notablysorrel. It is a commercial product used in photography, marble grinding, and removing ink stains.
Theanhydrous product is a white, odorless, crystalline solid, hygroscopic and soluble in water (2.5 g/100 g at room temperature). The solutions are basic. Below 50 °C the much less soluble "potassium tetraoxalate"K+[C2HO4]−·C2H2O4 forms and precipitates out of solution.[5]
The monohydrate KHC2O4·H2O starts losing the water at 100 °C.[6]
The anhydrous salt was found to have remarkableelastic anisotropy, due to itscrystal structure that consists of relatively rigid columns ofhydrogen-bonded hydrogenoxalate anions, joined into sheets byionic K–O bonds.[7]
Potassium hydrogenoxalate is strongly irritating to eyes, mucoses and gastrointestinal tract. It may cause cardiac failure and death.[5]
