Кальций азотнокислый

Описание

Calcium nitrate has the molecular formula of Ca(NO3)2 and the molecular weight of 164.0935 g/mol. Its CAS number is 10124-37-5. Calcium nitrate may be prepared by the reaction of nitric acid with calcium carbonate or calcium sulfide:
CaCO3 + 2HNO3 ? Ca(NO3)2 + CO +H2O
CaS + 2HNO3 ? Ca(NO3)2 +H2S
It is very soluble and forms a tetrahydrate, Ca(NO3) 2·4H2O if the solution is evaporated to dryness. The CAS number of the anhydrate is 10124-37-5 while that of the tetrahydrate is 13477-34-4. As with the beryllium nitrate salts, variation of the nitric acid concentration affects the type of hydrate produced. The trihydrate is known (CAS number 10124-37-5) but not the monohydrate. The anhydrate is a white cubic crystal that is hygroscopic; its density is 2.504 g/cm3 and it melts at 561°C. This salt is highly soluble in water and also dissolves in alcohols and acetone. The tetrahydrate melts in its own waters of hydration at 42.7°C and loses 4H2O molecules at 132°C. It decomposes to form nitrogen oxides and CaO similar to the behavior of the other alkaline earth nitrates. The anhydrous salt is soluble at 121.2 g/100 ml at 20°C and 271.2 g/100 ml at 40°C.

Химические свойства

White, deliquescent mass. Soluble in water, alcohol, and acetone.

Физические свойства

White cubic crystal; hygroscopic; density 2.50g/cm³; melts at 561°C; highly soluble in water; also dissolves in alcohols and acetone.

Использование

Calcium nitrate is mainly used as a component in fertilizers. Nitrocalcite is the name for a mineral which is a hydrated calcium nitrate that forms as an efflorescence in places where manure contacts limestone (or concrete) in a dry environment such as caverns or stables.Calcium nitrate is used in explosives, matches and pyrotechnics. Other applications are in the manufacture of incandescent mantle; and as an additive to diesel fuel for corrosion inhibition.This calciumnitrate is useful as an oxidizer but its hygroscopic nature, results in extreme deliquescence in air. Calcium nitrate is mainly used as a flocculent in rubber latex and in refrigerant manufacture. And it is also employed in oil exploratory wells and sewage treatment. In agriculture, it is used in hydroponic culture and as a fast-effective fertilizer for acid soil. It can also be used to make fireworks, to produce explosives in national defense industry, and to paint negative poles in the electronic instrument industry. It is also a raw material in making other nitrates. It is this usage that calcium nitrate finds most of its employment in industry, other than its use in agriculture. Calcium nitrate is a strong oxidizing agent. Mixing it with organic substances such as fuel oil or hydrocarbons or other oxidizable compounds can cause an explosion. Calcium nitrate has been evaluated as a component for heat storage devices.

Определение

calcium nitrate: A white deliquescentcompound, Ca(NO₃)₂, that isvery soluble in water; cubic; r.d. 2.50;m.p. 561°C. It can be prepared byneutralizing nitric acid with calciumcarbonate and crystallizing it fromsolution as the tetrahydrateCa(NO₃)₂.4H₂O, which exists in twomonoclinic crystalline forms (α, r.d.1.9; β, r.d. 1.82). There is also a trihydrate,Ca(NO₃)₂.3H₂O. The anhydroussalt can be obtained from the hydrateby heating but it decomposeson strong heating to give the oxide,nitrogen dioxide, and oxygen. Calciumnitrate is sometimes used as anitrogenous fertilizer.

Подготовка

Calcium nitrate may be prepared by the reaction of nitric acid with calcium carbonate or calcium sulfide:
CaCO₃ + 2HNO₃ →Ca(NO₃)₂ + CO + H2O
CaS + 2HNO₃ →Ca(NO₃)₂ + H2S

Общее описание

White to light gray granular solid. May be either the anhydrous compound or the tetrahydrate. Used in fertilizers, explosives and pyrotechnics.

Реакции воздуха и воды

Deliquescent. Water soluble.

Профиль реактивности

An oxidizing agent. Noncombustible but accelerates the burning of combustible materials. If large quantities are involved in the fire or the combustible material is finely divided an explosion may result. Prolonged exposure to fire or heat may result in an explosion. May explode if shocked or heated [Hawley]. Heating causes release of toxic oxides of nitrogen. Mixtures with alkyl esters may explode owing to the formation of alkyl nitrates; mixtures with phosphorus, tin(II) chloride, or other reducing agents may react explosively [Bretherick 1979 p. 108-109].

Опасность

Strong oxidizer, dangerous fire risk in con- tact with organic materials, may explode if shocked or heated.

Угроза здоровью

Dust causes mild irritation of eyes.

Сельскохозяйственное использование

Calcium nitrate [Ca(NO₃)₂], also known as lime nitrate, nitrocalcite, lime saltpeter and Norwegian saltpeter, was the first chemical nitrogenous fertilizer to be marketed.
Calcium nitrate fertilizer absorbs considerable amount of water, which makes it somewhat difficult to handle. It contains 15 % nitrogen and 21 % calcium. In a prilled form, it becomes suitable for bulk mixing and the powdered form is useful in sprays.
Calcium nitrate controls the blossom-end rot of tomatoes and is used in Europe as a major source of nitrogen.
Calcium nitrate used on saline soils displaces sodium with calcium. In addition, calcium nitrate is a non-acid forming fertilizer and improves physical properties of acidic and exhausted soils. However, its advantage as a fertilizer is offset by its extreme hygroscopic nature. This calls for its production in air-conditioned plants and the use of sealed moisture proof bags.
Calcium nitrate, in addition to its usage as a fertilizer, finds application in explosives, pyrotechnics, and inorganic chemical operations.

Профиль безопасности

A poison by ingestion. An irritant. A strong oxidant. Forms powerfully explosive mixtures with aluminum + ammonium nitrate + formamide + water, ammonium nitrate + hydrocarbon oils, ammonium nitrate + water-soluble fuels, and organic materials. When heated to decomposition it emits toxic fumes of NOx. See also NITRATES and CALCIUM COMPOUNDS.