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| Calcium nitrate | |
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| Other names | Kalksalpeter, nitrocalcite |
| Identifiers | |
| CAS number | [10124-37-5 (tetrahydrate: 13477-34-4)] |
| Properties | |
| Molecular formula | CaN2O6 |
| Molar mass | 164.00 g/mol |
| Appearance | colourless |
| Density | 2.504 g/cm3 (1.896 g/cm3 for monoclinic, tetrahydrate) |
| Melting point |
561 °C |
| Solubility in water | miscible |
| Structure | |
| Crystal structure | cubic (anhydrous) |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Calcium nitrate, also called Norgessalpeter (Norwegian saltpeter) is the inorganic compound with the formula Ca(NO3)2. This colourless salt absorbs moisture from the air and is commonly found as a tetrahydrate. It is mainly used as a component in fertilizers. Nitrocalcite is the name for hydrated calcium nitrate that forms as an efflorescence where manure contacts concrete or limestone in a dry environment as in stables or caverns.[1]
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Production and reactivity
Norgessalpeter was the first nitrogen fertilizer compound to be manufactured. Production began at Notodden, Norway in 1905. Most of the world's calcium nitrate is now made in Porsgrunn. It is produced by treating limestone with nitric acid, followed by neutralization with ammonia:
- CaCO3 + 2 HNO3 → Ca(NO3)2 + CO2 + H2O
It is also a byproduct of the Odda Process for the extraction of calcium phosphate:
- Ca3(PO4)2 + 6 HNO3 + 12 H2O → 2 H3PO4 + 3 Ca(NO3)2 + 12 H2O
Like related alkaline earth metal nitrates (as well as LiNO3), calcium nitrate decomposes upon heating to release nitrogen dioxide:[1]
- 2 Ca(NO3)2 → 2 CaO + 4 NO2 + O2 ΔH = 369 kJ/mol
Use in fertilizer
The fertilizer grade (15.5-0-0 + 19% Ca) is popular in the greenhouse and hydroponics trades; it contains ammonium nitrate and water, as the "double salt" 5Ca(NO3)2.NH4NO3.10H2O. Formulations lacking ammonia are also known: Ca(NO3)2.4H2O (12.8-0-0 + 18.3%Ca). An anhydrous, air-stable derivative is the urea complex Ca(NO3)2.4[OC(NH2)2.
References
- ^ a b Wolfgang Laue, Michael Thiemann, Erich Scheibler, Karl Wilhelm Wiegand “Nitrates and Nitrites” in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim.doi:10.1002/14356007.a17_265. Article Online Posting Date: June 15, 2000
External links
