| IUPAC name |
3D model (JSmol)
CompTox Dashboard (EPA)
|Density||2.20 g/cm3, monohydrate|
|Melting point||200 °C (392 °F; 473 K)decomposes (monohydrate)|
|0.67 mg/L (20 °C)|
|Main hazards||Harmful, Irritant|
|NFPA 704 (fire diamond)|
| Calcium carbonate |
| Sodium oxalate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Calcium oxalate (in archaic terminology, oxalate of lime) is a calcium salt of oxalate with the chemical formula CaC2O4·(H2O)x, where x varies from 0 to 3. All forms are colorless or white. The monohydrate occurs naturally as the mineral whewellite, forming envelope-shaped crystals, known in plants as raphides. The rarer dihydrate (mineral: weddellite) and trihydrate (mineral: caoxite) are also recognized. Calcium oxalates are a major constituent of human kidney stones. Calcium oxalate is also found in beerstone, a scale that forms on containers used in breweries.
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 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.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.
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.
Calcium oxalate can produce sores and numbing on ingestion and may even be fatal.
The monohydrate and dihydrate can be distinguished by the shape of the respective crystals.
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.
Calcium oxalate is used in the manufacture of ceramic glazes.
Kidney stone disease, also known as urolithiasis, is when a solid piece of material develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine stream. A small stone may pass without causing symptoms. If a stone grows to more than 5 millimeters (0.2 in), it can cause blockage of the ureter, resulting in severe pain in the lower back or abdomen. A stone may also result in blood in the urine, vomiting, or painful urination. About half of people who have had a kidney stone will have another within ten years.
A bladder stone is a stone found in the urinary bladder.
Ultrastructure is the architecture of cells and biomaterials that is visible at higher magnifications than found on a standard optical light microscope. This traditionally meant the resolution and magnification range of a conventional transmission electron microscope (TEM) when viewing biological specimens such as cells, tissue, or organs. Ultrastructure can also be viewed with scanning electron microscopy and super-resolution microscopy, although TEM is a standard histology technique for viewing ultrastructure. Such cellular structures as organelles, which allow the cell to function properly within its specified environment, can be examined at the ultrastructural level.
Oxalic acid is an organic compound with the formula C2H2O4. It is a white crystalline solid that forms a colorless solution in water. Its condensed formula is HOOCCOOH, reflecting its classification as the simplest dicarboxylic acid.
Clinical urine tests are various tests of urine for diagnostic purposes. A urinalysis (UA) is one of the most common methods of medical diagnosis. The word is a portmanteau of the words urine and analysis. Other tests are urine culture and urine electrolyte levels.
Oxalate (IUPAC: ethanedioate) is the dianion with the formula C
4, also written (COO)2−
2. Either name is often used for derivatives, such as salts of oxalic acid, for example sodium oxalate Na2C2O4, or dimethyl oxalate ((CH3)2C2O4). Oxalate also forms coordination compounds where it is sometimes abbreviated as ox.
Weddellite (CaC2O4·2H2O) is a mineral form of calcium oxalate named for occurrences of millimeter-sized crystals found in bottom sediments of the Weddell Sea, off Antarctica. Occasionally, weddellite partially dehydrates to whewellite, forming excellent pseudomorphs of grainy whewellite after weddellite's short tetragonal dipyramids. It was first described in 1942.
A calculus, often called a stone, is a concretion of material, usually mineral salts, that forms in an organ or duct of the body. Formation of calculi is known as lithiasis. Stones can cause a number of medical conditions.
Sodium oxalate, or disodium oxalate, is the sodium salt of oxalic acid with the formula Na2C2O4. It is a white, crystalline, odorless solid, that decomposes above 290 °C.
Feline lower urinary tract disease (FLUTD) is any disorder affecting the bladder or urethra of cats.
Raphides are needle-shaped crystals of calcium oxalate as the monohydrate or calcium carbonate as aragonite, found in more than 200 families of plants. Both ends are needle-like, but raphides tend to be blunt at one end and sharp at the other.
Oxalis pes-caprae is a species of tristylous flowering plant in the wood sorrel family Oxalidaceae. Oxalis cernua is a less common synonym for this species.
Bladder stones or uroliths are a common occurrence in animals, especially in domestic animals such as dogs and cats. Occurrence in other species, including tortoises, has been reported as well. The stones form in the urinary bladder in varying size and numbers secondary to infection, dietary influences, and genetics. Stones can form in any part of the urinary tract in dogs and cats, but unlike in humans, stones of the kidney are less common and do not often cause significant disease, although they can contribute to pyelonephritis and chronic kidney disease. Types of stones include struvite, calcium oxalate, urate, cystine, calcium phosphate, and silicate. Struvite and calcium oxalate stones are by far the most common.
Dimethyl oxalate is the organic compound with the formula (CH3O2C)2. It is the dimethyl ester of oxalic acid. Dimethyl oxalate is a colorless or white solid that is soluble in water.
Nephrocalcinosis, once known as Albright's calcinosis after Fuller Albright, is a term originally used to describe deposition of calcium salts in the renal parenchyma due to hyperparathyroidism. The term nephrocalcinosis is used to describe the deposition of both calcium oxalate and calcium phosphate. It may cause acute kidney injury. It is now more commonly used to describe diffuse, fine, renal parenchymal calcification on radiology. It is caused by multiple different conditions and is determined progressive kidney dysfunction. These outlines eventually come together to form a dense mass. During its early stages, nephrocalcinosis is visible on x-ray, and appears as a fine granular mottling over the renal outlines. It is most commonly seen as an incidental finding with medullary sponge kidney on an abdominal x-ray. However, it may be severe enough to cause renal tubular acidosis or even end stage renal failure, due to disruption of the renal tissue by the deposited calcium.
Ethylene glycol poisoning is poisoning caused by drinking ethylene glycol. Early symptoms include intoxication, vomiting and abdominal pain. Later symptoms may include a decreased level of consciousness, headache, and seizures. Long term outcomes may include kidney failure and brain damage. Toxicity and death may occur after drinking even a small amount.
Crystal arthropathy is a class of joint disorder that is characterized by accumulation of tiny crystals in one or more joints. Polarizing microscopy and application of other crystallographic techniques have improved identification of different microcrystals including monosodium urate, calcium pyrophosphate dihydrate, calcium hydroxyapatite, and calcium oxalate.
A druse is a group of crystals of calcium oxalate, silicates, or carbonates present in plants, and are thought to be a defense against herbivory due to their toxicity. Calcium oxalate (Ca(COO)2, CaOx) crystals are found in algae, angiosperms and gymnosperms in a total of more than 215 families. These plants accumulate oxalate in the range of 3–80% (w/w) of their dry weight through a biomineralization process in a variety of shapes. Araceae have numerous druses, multi-crystal druses and needle-shaped raphide crystals of CaOx present in the tissue. Druses are also found in leaves and bud scales of Prunus, Rosa, Allium, Vitis, Morus and Phaseolus.
Ammonium oxalate, C2H8N2O4 – more commonly written as (NH4)2C2O4 – is an oxalate salt with ammonium (sometimes as a monohydrate). It is a colorless (white) salt under standard conditions and is odorless and non-volatile. It is the ammonium salt of oxalic acid, and occurs in many plants and vegetables.
Renal stone formation and passage during space flight can potentially pose a severe risk to crew member health and safety and could affect mission outcome. Although renal stones are routinely and successfully treated on Earth, the occurrence of these during space flight can prove to be problematic.