Оксалата кальция (в архаическом терминологии, щавелевая известь ) является кальцием солью из оксалата с химической формулой CaC 2 О 4 · (H два вывод) х , где X изменяется от 0 до 3. всех форм бесцветные или белые. Моногидрат встречается в природе в виде минерала уевеллита , образуя кристаллы в форме оболочки, известные в растениях как рафиды . Также известны более редкие дигидрат (минерал: ведделлит ) и тригидрат (минерал: каоксит ). Оксалаты кальция являются одним из основных компонентов камней в почках человека.. Оксалат кальция также содержится в пивном камне - накипи, которая образуется на контейнерах, используемых на пивоваренных заводах .
Имена | |
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Название ИЮПАК Оксалат кальция | |
Идентификаторы | |
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3D модель ( JSmol ) | |
ЧЭБИ | |
ЧЭМБЛ | |
ChemSpider | |
ECHA InfoCard | 100.008.419 |
Номер ЕС |
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КЕГГ | |
PubChem CID | |
UNII |
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Панель управления CompTox ( EPA ) | |
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Характеристики | |
CaC 2 H 2 O 5 (моногидрат) CaC 2 O 4 (безводный) | |
Молярная масса | 128,097 г / моль |
Появление | белое твердое вещество |
Плотность | 2,20 г / см 3 , моногидрат [1] |
Температура плавления | 200 ° C (392 ° F, 473 K) разлагается (моногидрат) |
0,67 мг / л (20 ° С) | |
Опасности | |
Основные опасности | Вредный, Раздражающий |
Пиктограммы GHS | |
Сигнальное слово GHS | Предупреждение |
H302 , H312 | |
P280 | |
NFPA 704 (огненный алмаз) | |
Родственные соединения | |
Другие анионы | Карбонат кальция Ацетат кальция Формиат кальция |
Другие катионы | Оксалат натрия Оксалат бериллия Оксалат магния Оксалат стронция Оксалат бария Оксалат радия Оксалат железа (II) Оксалат железа (III) |
Родственные соединения | Щавелевая кислота |
Если не указано иное, данные приведены для материалов в их стандартном состоянии (при 25 ° C [77 ° F], 100 кПа). | |
проверить ( что есть ?) | |
Ссылки на инфобоксы | |
Вхождение
Many plants accumulate calcium oxalate as it has been reported in more than 1000 different genera of plants.[2] The calcium oxalate accumulation is linked to the detoxification of calcium (Ca2+) in the plant.[3]
The poisonous plant dumb cane (Dieffenbachia) contains the substance and on ingestion can prevent speech and be suffocating. It is also found in sorrel, rhubarb (in large quantities in the leaves), cinnamon, turmeric 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 genus Philodendron 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 removed in a cleaning process, beerstone will leave an unsanitary surface that can harbour microorganisms.[4] 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.
Calcium oxalate crystals in the urine are the most common constituent of human kidney stones, and calcium oxalate crystal formation is also one of the toxic effects of ethylene glycol poisoning.
Химические свойства
Calcium oxalate is a combination of calcium ions and the conjugate base of oxalic acid, the oxalate anion. The aqueous solution is slightly basic, due to the basicity of the oxalate ion. The basicity of it is weaker than sodium oxalate, due to the solubility of the compound.
Медицинское значение
Calcium oxalate can produce sores and numbing on ingestion and may even be fatal.
Morphology and diagnosis
The monohydrate and dihydrate can be distinguished by the shape of the respective crystals.
- Calcium oxalate dihydrate crystals are octahedral. A large portion of the crystals in a urine sediment will have this type of morphology, as they can grow at any pH and naturally occur in normal urine.
- Calcium oxalate monohydrate crystals vary in shape, and can be shaped like dumbbells, spindles, ovals, or picket fences, the last of which is most commonly seen due to ethylene glycol poisoning.[5]
Urine microscopy showing calcium oxalate crystals in the urine. The octahedral crystal morphology is clearly visible.
Urine microscopy showing a calcium oxalate monohydrate crystal (dumbbell shaped) and a calcium oxalate dihydrate crystal (envelope shaped) along with several erythrocytes.
Urine microscopy showing several calcium oxalate monohydrate crystals (dumbbell shaped, some of them clumped) and a calcium oxalate dihydrate crystal (envelope shaped) along with several erythrocytes.
Urinary sediment showing several calcium oxalate crystals. 40X
Kidney stones
About 80% of kidney stones are partially or entirely of the calcium oxalate type. They form when urine is persistently saturated with calcium and oxalate. Some of the oxalate in urine is produced by the body. Calcium and oxalate in the diet play a part, but are not the only factors that affect the formation of calcium oxalate stones. Dietary oxalate is an organic ion found in many vegetables, fruits, and nuts. Calcium from bone may also play a role in kidney stone formation.
Промышленное применение
Calcium oxalate is used in the manufacture of ceramic glazes.[6]
Смотрите также
- Oxalic acid
- Sodium oxalate
Рекомендации
- ^ a b S. Deganello (1981). "The Structure of Whewellite, CaC2O4.H2O, at 328 K". Acta Crystallogr. B. 37 (4): 826–829. doi:10.1107/S056774088100441X.
- ^ Francesci, V.R.; Nakata (2005). "Calcium oxalate in plants: formation and function". Annu Rev Plant Biol. 56 (56): 41–71. doi:10.1146/annurev.arplant.56.032604.144106.
- ^ Martin, G; Matteo Guggiari; Daniel Bravo; Jakob Zopfi; Guillaume Cailleau; Michel Aragno; Daniel Job; Eric Verrecchia; Pilar Junier (2012). "Fungi, bacteria and soil pH: the oxalate–carbonate pathway as a model for metabolic interaction". Environmental Microbiology. 14 (11): 2960–2970. doi:10.1111/j.1462-2920.2012.02862.x. PMID 22928486.
- ^ Ryan, James (27 May 2018). "What is beerstone (and how to remove it)". Retrieved 28 May 2018.
- ^ "Urine Crystals". ahdc.vet.cornell.edu/. Cornell University. Retrieved 12 July 2014.
- ^ "Calcium Oxalate Data Sheet". Hummel Croton Inc. Retrieved 23 April 2017.