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3D model (JSmol) | |
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| ECHA InfoCard | 100.030.289 |
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| UN number | 1454 |
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| Properties | |
| Ca(NO3)2 | |
| Molar mass |
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| Appearance | colorless solid (hygroscopic) |
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| Solubility inacetone | 33.08 g/100g (anhydrous, 25 °C (77 °F))[1] |
| Acidity (pKa) | 6.0 |
| −45.9×10−6 cm3/mol | |
| Structure | |
| cubic (anhydrous) monoclinic (tetrahydrate) | |
| Hazards | |
| GHS labelling: | |
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| Danger | |
| H272,H302,H315,H319 | |
| P210,P220,P221,P264,P270,P280,P301+P312,P302+P352,P305+P351+P338,P310,P321,P330,P332+P313,P337+P313,P362,P370+P378,P501 | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 302 mg/kg (rat, oral) |
| Safety data sheet (SDS) | ICSC 1037 |
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Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Calcium nitrate areinorganic compounds with the formulaCa(NO3)2·(H2O)x. The anhydrous compound, which is rarely encountered,absorbs moisture from the air to give thetetrahydrate. Both anhydrous and hydrated forms are colourlesssalts. Hydrated calcium nitrate, also calledNorgessalpeter (Norwegian salpeter), is mainly used as a component infertilizers, but it has other applications.Nitrocalcite is the name for a mineral which is a hydrated calcium nitrate that forms as anefflorescence wheremanure contactsconcrete orlimestone in a dry environment as in stables orcaverns. A variety of related salts are known including calciumammonium nitrate decahydrate and calciumpotassium nitrate decahydrate.[2]
Norgessalpeter was synthesized atNotodden,Norway in 1905 by theBirkeland–Eyde process. Most of the world's calcium nitrate is now made inPorsgrunn. It is produced by treating limestone withnitric acid, followed by neutralization with ammonia:
It is also an intermediate product of theOdda Process:
It can also be prepared from an aqueous solution ofammonium nitrate, andcalcium hydroxide:
Like relatedalkaline earth metal nitrates, calcium nitrate decomposes upon heating (starting at 500 °C (932 °F)) to releasenitrogen dioxide:[2]
The fertilizer grade (15.5-0-0 + 19% Ca) is popular in thegreenhouse andhydroponics trades; it containsammonium nitrate andwater, as the "double salt"5Ca(NO3)2·NH4NO3·10H2O. This is calledcalcium ammonium nitrate and often the name calcium nitrate prill is used as it always comes in a prilled (granular) form. Formulations lacking ammonia are also known:Ca(NO3)2·4H2O (11.9-0-0 + 16.9 Ca) and the water-free 17-0-0 + 23.6 Ca. A liquid formulation (9-0-0 + 11 Ca) is also offered. Ananhydrous, air-stable derivative is the ureacomplexCa(NO3)2·4[OC(NH2)2], which has been sold as Cal-Urea.[citation needed]
Calcium nitrate is also used to control certain plant diseases. For example, dilute calcium nitrate (andcalcium chloride) sprays are used to control bitter pit and cork spot in apple trees.[3]
Calcium nitrate is used in waste water pre-conditioning for odour emission prevention. The waste water pre-conditioning is based on establishing an anoxic biology in the waste water system. In the presence of nitrate, the metabolism for sulfates stops, thus preventing formation of hydrogen sulfide.[4] Additionally, easily degradable organic matter is consumed, which otherwise can cause anaerobic conditions downstream as well as odour emissions itself. The concept is also applicable for surplus sludge treatment.[5]
Calcium nitrate is used in concrete admixtures to accelerate setting. This use withconcrete andmortar is based on two effects. The calcium ion accelerates formation of calcium hydroxide and thus precipitation and setting. This effect is used also in cold weather concreting agents as well as some combinedplasticizers.[6] The nitrate ion leads to formation of iron hydroxide, whose protective layer reduces corrosion of the concrete reinforcement.[7]
Calcium nitrate is a very common coagulant in latex production, especially in dipping processes. Dissolved calcium nitrate is a part of the dipping bath solution. The warm former is dipped into the coagulation liquid and a thin film of the dipping liquid remains on the former. When now dipping the former into the latex the calcium nitrate will break up the stabilization of the latex solution and the latex will coagulate on the former.[8]
The dissolution of calcium nitrate tetrahydrate is highly endothermic (cooling). For this reason, calcium nitrate tetrahydrate is sometimes used for regenerable cold packs.[2]
Calcium nitrate can be used as a part of molten salt mixtures. Typical are binary mixtures of calcium nitrate andpotassium nitrate or ternary mixtures including alsosodium nitrate.[9][10][better source needed] Those molten salts can be used to replace thermo oil in concentrated solar power plants for the heat transfer, but mostly those are used in heat storage.[citation needed]
