Calcium nitrate

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Calcium nitrate
picture of constituent ions
Dusičnan vápenatý.JPG
Names
Other names
Kalksalpeter, nitrocalcite, Norwegian saltpeter, lime nitrate
Identifiers
10124-37-5 YesY
13477-34-4 (tetrahydrate)
ChemSpider 23336 YesY
Jmol 3D model Interactive image
PubChem 24963
RTECS number EW2985000
UN number 1454
  • InChI=1S/Ca.2NO3/c;2*2-1(3)4/q+2;2*-1 YesY
    Key: ZCCIPPOKBCJFDN-UHFFFAOYSA-N YesY
  • InChI=1/Ca.2NO3/c;2*2-1(3)4/q+2;2*-1
    Key: ZCCIPPOKBCJFDN-UHFFFAOYAF
  • [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O
Properties
Ca(NO3)2
Molar mass 164.088 g/mol (anhydrous)
236.15 g/mol (tetrahydrate)
Appearance colorless solid
hygroscopic
Density 2.504 g/cm3 (anhydrous)
1.896 g/cm3 (tetrahydrate)
Melting point 561 °C (1,042 °F; 834 K) (anhydrous)
42.7 °C (109 °F; 316 K) (tetrahydrate)
Boiling point decomposes (anhydrous)
132 °C (270 °F; 405 K) (tetrahydrate)
anhydrous:
1212 g/L (20 °C)
2710 g/L (40 °C)
tetrahydrate:
1950 g/L (0 °C)
1290 g/L (20 °C)
3630 g/L (100 °C)
Solubility soluble in ammonia
almost insoluble in nitric acid
Solubility in ethanol 51.4 g/100 g (20 °C)
62.9 g/100 g (40 °C)[1]
Solubility in methanol 134 g/100 g (10 °C)
144 g/100 g (40 °C)
158 g/100 g (60 °C)[1]
Solubility in acetone 16.8 g/kg (20 °C)[1]
Acidity (pKa) 6.0
Structure
cubic (anhydrous)
monoclinic (tetrahydrate)
Vapor pressure {{{value}}}
Related compounds
Other anions
 Calcium sulfate
Calcium chloride
Other cations
 Magnesium nitrate
Strontium nitrate
Barium nitrate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

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 but has other applications. Nitrocalcite is the name for a mineral which is a hydrated calcium nitrate that forms as an efflorescence where manure contacts concrete or limestone in a dry environment as in stables or caverns. A variety of related salts are known including calcium ammonium nitrate decahydrate and calcium potassium nitrate decahydrate.[2]

Production and reactivity

Norgessalpeter was the first synthetic nitrogen fertilizer compound to be manufactured. Production began at Notodden, Norway in 1905 by the Birkeland–Eyde process. 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 an intermediate product of the Odda Process:

Ca3(PO4)2 + 6 HNO3 + 12 H2O → 2 H3PO4 + 3 Ca(NO3)2 + 12 H2O

It can also be prepared from an aqueous solution of ammonium nitrate, and calcium hydroxide:

2 NH4NO3 + Ca(OH)2 → Ca(NO3)2 + 2 NH4OH

Like related alkaline earth metal nitrates, calcium nitrate decomposes upon heating (starting at 500 °C) to release nitrogen dioxide:[2]

2 Ca(NO3)2 → 2 CaO + 4 NO2 + O2 ΔH = 369 kJ/mol

Applications

Use in fertilizer

As of 1978, only 170,000 tons/year were produced for applications in fertilizers.[2] 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. This is called calcium ammonium nitrate. Formulations lacking ammonia are also known: Ca(NO3)2·4H2O (11.9-0-0 + 16.9%Ca). A liquid formulation (9-0-0 + 11% Ca) is also offered. An anhydrous, air-stable derivative is the urea complex Ca(NO3)2·4[OC(NH2)2], which has been sold as Cal-Urea.

Waste water treatment

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 sulphide.[3] Additionally easy 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.[4]

Concrete

Calcium nitrate is used in set accelerating concrete admixtures. This use with concrete and mortar 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 combined plasticizers.[5] The nitrate ion leads to formation of iron hydroxide, whose protective layer reduces corrosion of the concrete reinforcement.[6]

Cold packs

The dissolution of calcium nitrate tetrahydrate is highly endothermic (cooling). For this reason, calcium nitrate tetrahydrate is sometimes used for regenerable cold packs.[2]

References

  1. ↑ 1.0 1.1 1.2 Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ 2.0 2.1 2.2 2.3 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
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Justines, H. (2010) "Calcium Nitrate as a Multifunctional Concrete Admixture" Concrete Magazine, Vol 44, No1, p.34. ISSN: 0010-5317
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found.
Salts and covalent derivatives of the Nitrate ion
HNO3 He
LiNO3 Be(NO3)2 B(NO3)4− C N O FNO3 Ne
NaNO3 Mg(NO3)2 Al(NO3)3 Si P S ClONO2 Ar
KNO3 Ca(NO3)2 Sc(NO3)3 Ti(NO3)4 VO(NO3)3 Cr(NO3)3 Mn(NO3)2 Fe(NO3)3 Co(NO3)2,
Co(NO3)3		 Ni(NO3)2 Cu(NO3)2 Zn(NO3)2 Ga(NO3)3 Ge As Se Br Kr
RbNO3 Sr(NO3)2 Y Zr(NO3)4 Nb Mo Tc Ru Rh Pd(NO3)2 AgNO3 Cd(NO3)2 In Sn Sb Te I Xe(NO3)2
CsNO3 Ba(NO3)2   Hf Ta W Re Os Ir Pt Au Hg2(NO3)2,
Hg(NO3)2		 Tl(NO3)3 Pb(NO3)2 Bi(NO3)3 Po At Rn
Fr Ra   Rf Db Sg Bh Hs Mt Ds Rg Cn Uut Fl Uup Lv Uus Uuo
↓
La Ce(NO3)3,
Ce(NO3)4		 Pr Nd Pm Sm Eu Gd(NO3)3 Tb Dy Ho Er Tm Yb Lu
Ac Th Pa UO2(NO3)2 Np Pu Am Cm Bk Cf Es Fm Md No Lr
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