Calcium oxalate

Description

Calcium oxalate (in archaic terminology, oxalate of lime) is a chemical compound that forms envelope-shaped crystals, known in plants as raphides. A major constituent of human kidney stones, the chemical is also found in beerstone, a scale that forms on containers used in breweries. Its chemical formula is CaC₂O₄ or Ca (COO)₂.

Chemical properties

Calcium oxalate is white precipitate, insoluble in weak acids, but soluble in strong acids, formed by reaction of soluble calcium salt solution and ammonium oxalate solution. Solubility at 18 °C 0.0056 g anhydrous salt per liter of saturated solution.

Physical properties

Most crystals look like a 6 sided prism and often look like a pointed picket from a wooden fence. More than 90 % of the crystals in a urine sediment will have this type of morphology. These other shapes are less common than the 6 sided prism, however it is important to be able to quickly identify them in case of emergency.

What are the applications of Application

Calcium oxalate is used in the manufacture of ceramic glazes.

General Description

Purity based on trace metal analysis

Nature sources

Oalcium oxalate crystals are commonly associated with free-living, pathogenic, and plant-symbiotic fungi and are formed by the reprecipitation of solubilized calcium as the oxalate. Fungal-derived calcium oxalate can exhibit a variety of crystalline forms (tetragonal, bipyramidal, plate-like, rhombohedral, or needles), which often associate with the outer surfaces of hyphae.

Ecological function

The formation of calcium oxalate by fungi has an important influence on biological and geochemical processes in soils, acting as a reservoir for calcium in the ecosystem, and also influencing phosphate availability.