Calcium oxalate

Calcium oxalate
Names

IUPAC name calcium ethanedioate
Identifiers
CAS Number	25454-23-3 (anhydrous)^Y 5794-28-5 (monohydrate)^N
3D model (Jmol)	Interactive image
ChEBI	CHEBI:60579^Y
ChemSpider	30549^Y
ECHA InfoCard	100.008.419
PubChem	16212978
InChI InChI=1S/C2H2O4.Ca/c3-1(4)2(5)6;/h(H,3,4)(H,5,6);/q;+2/p-2^Y Key: QXDMQSPYEZFLGF-UHFFFAOYSA-L^Y InChI=1/C2H2O4.Ca/c3-1(4)2(5)6;/h(H,3,4)(H,5,6);/q;+2/p-2 Key: QXDMQSPYEZFLGF-NUQVWONBAM
SMILES C(=O)(C(=O)[O-])[O-].[Ca+2]
Properties
Chemical formula	CaC₂O₄
Molar mass	128.097 g/mol, anhydrous 146.112 g/mol, monohydrate
Appearance	white solid
Density	2.12 g/cm³, anhydrous 2.12 g/cm³, monohydrate
Melting point	200 °C (392 °F; 473 K) decomposes (monohydrate)
Solubility in water	0.67 mg/L (20 °C)
Related compounds
Other cations	Beryllium oxalate Magnesium oxalate Strontium oxalate Barium oxalate Radium oxalate Iron(II) oxalate Iron(III) oxalate
Related compounds	Oxalic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N (what is ^YN ?)
Infobox references

Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula CaC₂O₄. It is a chemical compound that forms envelope-shaped crystals, known in plants as raphides. A major constituent of human kidney stones, calcium oxalate is also found in beerstone, a scale that forms on containers used in breweries.

Calcium oxalate is a poisonous substance that can produce sores and numbing on ingestion and may even be fatal. Many plants accumulate calcium oxalate as it has been reported in more than 1000 different genera of plants. The calcium oxalate accumulation is linked to the detoxification of calcium (Ca²⁺) in the plant.

The poisonous plant dumb cane (Dieffenbachia) contains the substance and on ingestion can prevent speech and be suffocating. It is also found in rhubarb (in large quantities in the leaves) and in species of Oxalis, Araceae, Arum Italicum, taro, kiwifruit, tea leaves, agaves, Virginia creeper (Parthenocissus quinquefolia), and Alocasia and in spinach in varying amounts. Plants of the Philodendron genus contain enough calcium oxalate that consumption of parts of the plant can result in uncomfortable symptoms. Insoluble calcium oxalate crystals are found in plant stems, roots, and leaves and produced in idioblasts.

Calcium oxalate, as ‘beerstone’, is a brownish precipitate that tends to accumulate within vats, barrels and other containers used in the brewing of beer. If not completely removed in a cleaning process, beerstone will leave an unsanitary surface that can harbour microorganisms. Beerstone is composed of calcium and magnesium salts and various organic compounds left over from the brewing process; it promotes the growth of unwanted microorganisms that can adversely affect or even ruin the flavour of a batch of beer.

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Wikipedia