calcium oxide

calcium oxide,

chemical compound, CaO, a colorless, cubic crystalline or white amorphous substance. It is also called lime, quicklime, or caustic lime, but commercial lime often contains impurities, e.g., silica, iron, alumina, and magnesia. It is prepared by heating calcium carbonatecalcium carbonate,
CaCO₃, white chemical compound that is the most common nonsiliceous mineral. It occurs in two crystal forms: calcite, which is hexagonal, and aragonite, which is rhombohedral.
..... Click the link for more information. (e.g., limestonelimestone,
sedimentary rock wholly or in large part composed of calcium carbonate. It is ordinarily white but may be colored by impurities, iron oxide making it brown, yellow, or red and carbon making it blue, black, or gray. The texture varies from coarse to fine.
..... Click the link for more information. ) in a special lime kiln to about 500&degC; to 600&degC;, decomposing it into the oxide and carbon dioxide. Calcium oxide is widely used in industry, e.g., in making porcelain and glass; in purifying sugar; in preparing bleaching powderbleaching powder,
white or nearly white powder that is usually a mixture of calcium chloride hypochlorite, CaCl(OCl); calcium hypochlorite, Ca(OCl)₂; and calcium chloride, CaCl₂.
..... Click the link for more information. , calcium carbide, and calcium cyanamide; in water softeners; and in mortars and cements. In agriculture it is used for treating acidic soils (limingliming
, application to the soil of calcium in various forms, generally as ground limestone, but also as marl, chalk, shells, or hydrated lime. Lime benefits soil by neutralizing acidity, improving texture, and increasing the activity of soil microorganisms.
..... Click the link for more information. ). It is incandescent when heated to high temperatures; the Drummond light, or limelight, provides a brilliant white light by heating a cylinder of lime with the flame of an oxyhydrogen torch. Calcium oxide is a basic anhydride, reacting with water to form calcium hydroxidecalcium hydroxide,
Ca(OH)₂, colorless crystal or white powder. It is prepared by reacting calcium oxide (lime) with water, a process called slaking, and is also known as hydrated lime or slaked lime. When heated above 580&degC; it dehydrates, forming the oxide.
..... Click the link for more information. ; during the reaction (slaking) much heat is given off and the solid nearly doubles its volume.

Calcium Oxide

(also quicklime), CaO, a compound of calcium and oxygen; colorless crystals with a density of 3.4 g/cm³ and a melting point of 2585°C. The industrial product is a white porous substance. Calcium oxide reacts vigorously with water, liberating a considerable amount of heat and forming calcium hydroxide: CaO + H₂O = Ca(OH)₂ (slaking process). Calcium oxide is obtained by the calcination of limestone or chalk. It is widely used in construction, the chemical industry, metallurgy, agriculture, and water purification.

calcium oxide

[′kal·se·əm ′äk‚sīd] (inorganic chemistry) CaO A caustic white solid sparingly soluble in water; the commercial form is prepared by roasting calcium carbonate limestone in kilns until all the carbon dioxide is driven off; used as a refractory, in pulp and paper manufacture, and as a flux in manufacture of steel. Also known as burnt lime; calx; caustic lime.

lime

A white or grayish-white caustic substance, calcium oxide, usually obtained by heating limestone or marble at a high temperature; used chiefly in plasters, mortars, and cements. In the past, in many areas along the seacoast where limestone was scarce, seashells were heated to obtain lime. See also hydrated lime, hydraulic lime, mortar, shell lime, slaked lime.

calcium oxide

a white crystalline base used in the production of calcium hydroxide and bleaching powder and in the manufacture of glass, paper, and steel. Formula: CaO

calcium oxide

calcium

(Ca) [kal´se-um] a chemical element, atomic number 20, atomic weight 40.08. (See Appendix 6.) Calcium is the most abundant mineral in the body. In combination with phosphorus it forms calcium phosphate, the dense, hard material of the bones and teeth. It is an important cation in intracellular and extracellular fluid and is essential to the normal clotting of blood, the maintenance of a normal heartbeat, and the initiation of neuromuscular and metabolic activities.
Within the body fluids calcium exists in three forms. Protein-bound calcium accounts for about 47 per cent of the calcium in plasma; most of it in this form is bound to albumin. Another 47 per cent of plasma calcium is ionized. About 6 per cent is complexed with phosphate, citrate, and other anions.
Ionized calcium is physiologically active. One of its most important physiological functions is control of the permeability of cell membranes. Parathyroid hormone, which causes transfer of exchangeable calcium from bone into the blood stream, maintains calcium homeostasis by preventing either calcium deficit or excess.
Hypercalcemia: This is when the level of serum calcium rises above normal; neuromuscular activity begins to diminish. Symptoms include lethargy, muscle weakness (which, as the level of calcium increases, can progress to depressed reflexes and hypotonic muscles), constipation, mental confusion, and coma. The heartbeat also slows, which potentiates the effects of digitalis.
Hypocalcemia: This is a serum level of calcium that is below normal; it is manifested by increased neuromuscular irritability. When there is a deficit of ionized calcium, the nerve cells become more permeable, allowing leakage of sodium and potassium from the cells. This produces excitation of the nerve fibers and triggers uncontrollable activity of the skeletal muscles. Hence, as the calcium level continues to drop, the patient begins to experience muscle twitching and cramping, grimacing, and carpopedal spasm, which can quickly progress to tetany, laryngospasm, convulsions, cardiac arrhythmias, and eventually to respiratory and cardiac arrest. Relatively early signs of hypocalcemia are a positive trousseau's sign and a positive chvostek's sign.
Dietary sources of calcium include dairy products (such as milk and cheese), soybeans, fortified orange juice, dark green leafy vegetables (such as mustard greens and broccoli), sardines, clams, and oysters. The allowance" >recommended dietary allowance of calcium for children aged 4 to 8 is 800 mg, and that for women aged 50 to 70 is 1200 mg. (See tables in the Appendices for recommended dietary allowances across the life span.) It is difficult to meet these requirements without including milk or milk products in the daily diet. The most familiar calcium deficiency disease is rickets, in which the bones and teeth soften. However, it is believed that a large number of people suffer from subclinical calcium deficiency because of poor eating habits. Since calcium is essential to the formation and maintenance of strong bones, an adequate intake is important in the prevention of osteoporosis.calcium acetate the calcium salt of acetic acid; administered orally as a source of calcium and as a binder" >phosphate binder, such as in patients with end-stage renal disease. Also used as a pharmaceutical buffering agent.calcium carbonate an insoluble salt occurring naturally in bone, shells, and chalk; used as an antacid, calcium supplement, and binder" >phosphate binder, and for treatment of osteoporosis.calcium channel blocker (calcium channel blocking agent) a drug such as nifedipine, diltiazem, or verapamil that selectively blocks the influx of calcium ions through a channel" >calcium channel of cardiac muscle and smooth muscle cells; used in the treatment of angina" >Prinzmetal's angina, chronic angina" >stable angina, and cardiac arrhythmias" >arrhythmias. Calcium channel blocking agents act to control arrhythmias by slowing the rate of sinoatrial node discharge and the conduction velocity through the atrioventricular node. They act in vasospastic angina to relax and prevent coronary artery spasm. The mechanism of action in classical angina is a lowering of myocardial oxygen utilization by dilating peripheral arteries and thereby reducing total peripheral resistance and the work of the heart.

Physiologic activity of calcium channel blockers. (Data from Hardman J. and Limbird L., editors: Goodman and Gilman's The Pharmacologic Basis of Therapeutics, 9th ed., New York, McGraw-Hill, 1996; and the National Institutes of Health: The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure, NIH Pub. No. 98-4080, Washington, DC, GPO, 1998.) From Edmunds and Mayhew, 2000.calcium chloride a salt used in solution to restore electrolyte balance, treat hypocalcemia, and act as a treatment adjunct in cardiac arrest and in magnesium poisoning.calcium citrate a salt used as a calcium replenisher; also used in the treatment of hyperphosphatemia in osteodystrophy" >renal osteodystrophy.calcium glubionate a calcium replenisher, used as a nutritional supplement and for the treatment of hypocalcemia; administered orally.calcium gluceptate a calcium salt administered intramuscularly or intravenously in the prevention and treatment of hypocalcemia and as an electrolyte replenisher.calcium gluconate a calcium salt administered intravenously or orally in the treatment and prevention of hypercalcemia and as a nutritional supplement. It is also administered by injection as a treatment adjunct in cardiac arrest and in the treatment of hyperkalemia.calcium hydroxide an astringent compound used topically in solution or lotions.calcium lactate a calcium replenisher, administered orally in the treatment and prevention of hypocalcemia and as a nutritional supplement.calcium oxalate a salt of oxalic acid, which in excess in the urine may lead to formation of oxalate calculi" >urinary calculi.calcium oxide lime (def. 1).calcium pantothenate a calcium salt of the dextrorotatory isomer of the B vitamin pantothenic acid; used as a nutritional supplement. It is also available as racemic calcium pantothenate, which is a mixture of the dextrorotatory and levorotatory isomeric forms.calcium phosphate a salt containing calcium and the phosphate radical; dibasic and tribasic calcium phosphate are used as sources of calcium.calcium polycarbophil a hydrophilic agent used as a bulk laxative.calcium propionate a salt used as an antifungal preservative in foods and as a topical antifungal agent.calcium pyrophosphate the pyrophosphate salt of calcium, used as a polishing agent in dentifrices. Crystals of the dihydrate form occur in the joints in calcium pyrophosphate deposition disease.calcium pyrophosphate deposition disease an acute or chronic inflammatory arthropathy caused by deposition of crystals of calcium pyrophosphate dihydrate in the joints and synovial fluid and chondrocalcinosis. Clinically, it may resemble numerous other connective tissue diseases such as arthritis and gout, or it may be asymptomatic. Acute attacks are sometimes called pseudogout.calcium sulfate a compound of calcium and sulfate, occurring as gypsum or as plaster of paris.

lime

(līm), 1. an alkaline earth oxide occurring in grayish white masses (quicklime); on exposure to the atmosphere it becomes converted into calcium hydrate and calcium carbonate (air-slaked lime); direct addition of water to calcium oxide produces calcium hydrate (slaked lime). Synonym(s): calcium oxide, calx (1) 2. Fruit of the lime tree, Citrus medica (family Rutaceae), which is a source of ascorbic acid and acts as an antiscorbutic agent. [O.E. līm, birdlime]

calcium oxide

A whitish, odourless crystal widely used in industry; it is poorly soluble in water, and reacts with water to form calcium hydroxide (CaOH), a base. It has a melting point of 2614ºC and a boiling point of 2850ºC.

Toxicity
Mucocutaneous and upper airway irritation, burns with oropharyngeal ulceration, abdominal pain, nausea and vomiting.

calcium oxide

calcium oxide

calcium oxide

calcium oxide

calcium oxide,

Calcium Oxide

calcium oxide

lime

calcium oxide

calcium oxide

calcium

lime

calcium oxide

calcium oxide

Synonyms for calcium oxide

noun a white crystalline oxide used in the production of calcium hydroxide

Synonyms

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