Nitrocalcite

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Nitrocalcite<ref>http://www.mindat.org/min-2919.html seen on 29.07.2010</ref>
HJS Ca(NO3)2 101703-10-1.jpg
Mineralogical name Nitrocalcite
Chemical name Calcium Nitrate Tetrahydrate
Trivial name Nitrate of lime
Chemical formula Ca(NO3)2•4H2O
Other forms Ca(NO3)2•2H2O (calcium nitrate dihydrate)
Ca(NO3)2•3H2O (calcium nitrate trihydrate)
Crystal system monoclinic
Crystal structure
Deliquescence humidity 20°C 53.06%
Solubility (g/l) at 20°C 7.726 mol/kg
Density (g/cm³) 1.82 g/cm3
Molar volume 129.8 cm3/mol
Molar weight 236.15 g/mol
Transparency transparent
Cleavage
Crystal habit
Twinning
Phase transition
Chemical behavior
Comments
Crystal Optics
Refractive Indices nx = 1.465
ny = 1.498
nz = 1.504
Birefringence Δ = 0.039
Optical Orientation negative
Pleochroism
Dispersion
Used Literature
[Steiger.etal:2014]Title: Weathering and Deterioration
Author: Steiger, Michael; Charola A. Elena; Sterflinger, Katja
Link to Google Scholar
[Broul.etal:1981]Title: Solubility in organic two component systems
Author: Broul M., Nyvlt J.; Soehnel O.
Link to Google Scholar


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Solubility

Figure 1 Solubility of calcium nitrate in water. The molality m [n(Ca(NO3)2•xH2O)•kg(H2O)-1] is plotted versus the temperature.


At 20 °C nitrocalcite is the stable phase of calcium nitrate. The salt has got a high solubilty in water and due to the temperature range of its stability it is relevant as a crystallizing phases under ambient conditions.

Hygroscopicity

Figure 2 Deliquescence behaviour of calcium nitrate. The water activity aw is plotted versus the temperature.


Table 1: Deliquescence humidities of nitrocalcite at different round temperatures [Steiger.etal:2014]Title: Weathering and Deterioration
Author: Steiger, Michael; Charola A. Elena; Sterflinger, Katja
Link to Google Scholar
0°C 10°C 20°C 30°C 40°C 50°C
63.8%r.h. 58.8%r.h. 53.1%r.h. 46.0%r.h. 35.5%r.h. 21.3%r.h. (Ca(NO3)2•3H2O)


Under the polarizing microscope

Weblinks

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Literature

[Broul.etal:1981]Elsevier (eds.) Broul M., Nyvlt J.; Soehnel O. (1981): Solubility in organic two component systems, ElsevierLink to Google Scholar
[Steiger.etal:2014]Steiger, Michael; Charola A. Elena; Sterflinger, Katja (2014): Weathering and Deterioration. In: Siegesmund S.; Snethlage R. (eds.): Stone in Architecture, Springer Verlag Berlin Heidelberg, 223-316, 10.1007/978-3-642-45155-3_4Link to Google Scholar