Editing Calcium oxalate (section)

{{Short description|Calcium salt of oxalic acid}}
{{Use dmy dates|date=April 2022}}
{{chembox
|Verifiedfields = changed
|Watchedfields = changed
|verifiedrevid = 443496090
|PIN = Calcium oxalate
|SystematicName = Calcium ethanedioate
|IUPACName =
|OtherNames = Oxalate of lime
|ImageFile = Calcium oxalate resonance.svg
|ImageSize = 150px
|ImageName = Calcium oxalate
|ImageFile1 = 246802-ICSDox.png
|ImageSize1 = 150px
|ImageName1 = structure of calcium oxalate monohydrate at 328 K
|ImageCaption1 = Structure of calcium oxalate monohydrate{{legend|mediumspringgreen|[[Calcium]], Ca}}{{legend|grey|[[Carbon]], C}}{{legend|red|[[Oxygen]], O}}{{legend|white|[[Hydrogen]], H}}
|Section1 = {{Chembox Identifiers
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
|ChemSpiderID = 30549
|InChI = 1/C2H2O4.Ca/c3-1(4)2(5)6;/h(H,3,4)(H,5,6);/q;+2/p-2
|InChIKey = QXDMQSPYEZFLGF-NUQVWONBAM
|ChEBI_Ref = {{ebicite|correct|EBI}}
|ChEMBL = 3184709
|ChEBI = 60579
|EINECS = 209-260-1
|KEGG = C17478
|SMILES = C(=O)(C(=O)[O-])[O-].[Ca+2]
|StdInChI_Ref = {{stdinchicite|correct|chemspider}}
|StdInChI = 1S/C2H2O4.Ca/c3-1(4)2(5)6;/h(H,3,4)(H,5,6);/q;+2/p-2
|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
|StdInChIKey = QXDMQSPYEZFLGF-UHFFFAOYSA-L
|CASNo_Ref = {{cascite|correct|??}}
|CASNo = 5794-28-5 
|CASNo_Comment = (monohydrate)
|CASNo2 = 25454-23-3 
|CASNo2_Comment = (dihydrate)
|CASNo3 = 192389-49-4 
|CASNo3_Comment = (trihydrate)
|CASNo2_Ref = {{cascite|changed|??}}
|UNII_Ref = {{fdacite|correct|FDA}}
|UNII = 4PP86KK527
|UNII_Comment = (monohydrate)
|PubChem = 16212978
}}
|Section2 = {{Chembox Properties
|Formula = {{chem2|CaC2O4}}
|Ca=1|C=2|O=4
|Appearance = colourless or white crystals (anhydrous and hydrated forms)
|Density = 2.20 g/cm<sup>3</sup>, monohydrate<ref name=Acta/>
|Solubility = 0.61 mg/(100 g) {{chem2|H2O}} (20&nbsp;°C)<ref>{{cite book |editor1-last=Haynes |editor1-first=W. |title=Handbook of Chemistry and Physics |date=2015–2016 |publisher=CRC Press |page=4-55 |edition=96th}}</ref>
|SolubilityProduct = 2.7 × 10<sup>−9</sup> for {{chem2|CaC2O4}}<ref name="Euler_Ksp">{{Cite web |title=K<sub>sp</sub> Table: Solubility product constants near 25 °C |author=Euler |work=chm.uri.edu |access-date=10 June 2021 |url= https://www.chm.uri.edu/weuler/chm112/refmater/KspTable.html |language=English}}</ref>
|MeltingPtC = 200
|MeltingPt_notes = decomposes (monohydrate)
}}
|Section3 = {{Chembox Hazards
|MainHazards = Harmful, Irritant
|GHSPictograms = {{GHS07}}
|GHSSignalWord = Warning
|HPhrases = {{H-phrases|302|312}}
|PPhrases = {{P-phrases|280}}
|NFPA-H = 2
|NFPA-F = 1
|NFPA-R = 1
|ExternalSDS = [https://www.fishersci.com/store/msds?partNumber=AC403880050&productDescription=CALCIUM+OXALATE+MONOHYDRATE+5G&vendorId=VN00032119&countryCode=US&language=en External SDS]
}}
|Section4 = {{Chembox Related
|OtherCations = [[Sodium oxalate]]<br />[[Beryllium oxalate]]<br/>[[Magnesium oxalate]]<br/>[[Strontium oxalate]]<br/>[[Barium oxalate]]<br/>[[Radium oxalate]]<br />[[Iron(II) oxalate]]<br />[[Iron(III) oxalate]]
|OtherAnions = [[Calcium carbonate]]<br />[[Calcium acetate]]<br />[[Calcium formate]]
|OtherCompounds = [[Oxalic acid]]
}}
}}
[[File:Surface of a kidney stone.jpg|thumb|260px|Scanning electron micrograph of the surface of a kidney stone showing tetragonal crystals of [[Weddellite]] (calcium oxalate dihydrate) emerging from the amorphous central part of the stone (the horizontal length of the picture represents 0.5 mm of the figured original)]]

'''Calcium oxalate''' (in archaic terminology, '''oxalate of lime''') is a [[calcium]] [[salt (chemistry)|salt]] of [[oxalic acid]] with the chemical formula {{chem2|CaC2O4}} or {{chem2|Ca(COO)2}}. It forms hydrates {{chem2|CaC2O4*''n''H2O}}, where ''n'' varies from 1 to 3. Anhydrous and all hydrated forms are colorless or white. The monohydrate {{chem2|CaC2O4*H2O}} occurs naturally as the mineral [[whewellite]], forming envelope-shaped crystals, known in plants as [[raphide]]s. The two rarer hydrates are dihydrate {{chem2|CaC2O4*2H2O}}, which occurs naturally as the mineral [[weddellite]], and trihydrate {{chem2|CaC2O4*3H2O}}, which occurs naturally as the mineral [[caoxite]], are also recognized. Some foods have high quantities of calcium oxalates and can produce sores and numbing on ingestion and may even be fatal. Cultural groups with diets that depend highly on fruits and vegetables high in calcium oxalate, such as those in [[Pandanus_tectorius#Uses|Micronesia]], reduce the level of it by boiling and cooking them.<ref name=Arno14>{{Citation |mode=cs1 |last1=Arnold |first1=Michael A. |year=2014 |title=''Pandanus tectorius'' S. Parkinson |website=Aggie Horticulture |publisher=Texas A&M University |url=https://aggie-horticulture.tamu.edu/syllabi/206/Lists/Fourth%20Edition/Pandanustectorius.pdf |access-date=30 September 2020 |archive-date=31 August 2021 |archive-url=https://web.archive.org/web/20210831185729/https://aggie-horticulture.tamu.edu/syllabi/206/Lists/Fourth%20Edition/Pandanustectorius.pdf |url-status=dead}}</ref><ref>{{Cite web|author=WebMD Editorial|title=Foods High in Oxalates|url=https://www.webmd.com/diet/foods-high-in-oxalates|access-date=30 January 2022|website=WebMD|language=en}}</ref> They are a constituent in 76% of human [[kidney stone disease|kidney stones]].<ref name="Singh">{{cite journal |last1=Singh |first1=Prince |last2=Enders |first2=Felicity T. |last3=Vaughan |first3=Lisa E. |last4=Bergstralh |first4=Eric J. |last5=Knoedler |first5=John J. |last6=Krambeck |first6=Amy E. |last7=Lieske |first7=John C. |last8=Rule |first8=Andrew D. |title=Stone Composition Among First-Time Symptomatic Kidney Stone Formers in the Community |journal=Mayo Clinic Proceedings |date=October 2015 |volume=90 |issue=10 |pages=1356–1365 |doi=10.1016/j.mayocp.2015.07.016|pmid=26349951 |pmc=4593754}}</ref> Calcium oxalate is also found in beerstone, a scale that forms on containers used in [[brewery|breweries]].