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Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalic acid with the chemical formula CaC 2 O 4 or Ca(COO) 2. It forms hydrates CaC 2 O 4 · n H 2 O , where n varies from 1 to 3.
Whewellite / ˈ h juː ə l aɪ t / is a mineral, hydrated calcium oxalate, formula Ca C 2 O 4 ·H 2 O. [6] Because of its organic content it is thought to have an indirect biological origin; this hypothesis is supported by its presence in coal and sedimentary nodules. However, it has also been found in hydrothermal deposits where a biological ...
Raphides in Epipremnum Devil's ivy (600× magnification). Raphides (/ ˈ r æ f ɪ d i z / RAF-id-eez; singular raphide / ˈ r eɪ f aɪ d / RAY-fyde or raphis) are needle-shaped crystals of calcium oxalate monohydrate (prismatic monoclinic crystals) or calcium carbonate as aragonite (dipyramidal orthorhombic crystals), found in more than 200 families of plants.
Weddellite, or calcium oxalate dihydrate, crystallises in a tetragonal system: the classic crystal shape is the eight-face bipyramid. Using bright field microscopy, the weddellite crystals are recognised easily by their shape, reminiscent of a postal envelope. More complex shapes of weddellite are possible; the dumbbell shape is not rare and ...
Oxalate (systematic IUPAC name: ethanedioate) is an anion with the chemical formula C 2 O 2− 4.This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (Na 2 C 2 O 4), and several esters such as dimethyl oxalate ((CH 3) 2 C 2 O 4).
Rhubarb leaves contain about 0.5% oxalic acid, and jack-in-the-pulpit (Arisaema triphyllum) contains calcium oxalate crystals. Similarly, the Virginia creeper, a common decorative vine, produces oxalic acid in its berries as well as oxalate crystals in the sap, in the form of raphides. Bacteria produce oxalates from oxidation of carbohydrates. [16]
Two types naturally occur, calcium oxalate monohydrate, or whewellite (CaC 2 O 4 ·H 2 O), and calcium oxalate dihydrate, or weddellite (CaC 2 O 4 ·2H 2 O). Their appearance can be rough, smooth, spiculated (needle-like), or jackstone. Calcium oxalate stones form more readily in animals with hypercalcaemia, which can be caused by Addison's ...
Calcium in a blood sample should be estimated when required medically. Calcium should be precipitated out of 0.1 mL of the blood sample serum as calcium oxalate. After that, the decomposition of the calcium oxalate should occur by heat. Then, the sample should be estimated colorimetrically by o-cresolphthalein complexone.