Sodium sulfate phase III

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Author: Amelie Stahlbuhk
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Sodium sulfate phase III
Mineralogical name
Chemical name sodium sulfate phase III
Trivial name
Chemical formula Na2SO4
Other forms Na2SO4•10H2O (Mirabilite)
Na2SO4•7H2O (Sodium sulfate heptahydrate)
Crystal system
Crystal structure
Deliquescence humidity 20°C 82.9 %
Solubility (g/l) at 20°C 4.428 mol/kg
Density (g/cm³)
Molar volume
Molar weight 142.04 g/mol
Transparency
Cleavage
Crystal habit
Twinning
Phase transition
Chemical behavior
Comments
Crystal Optics
Refractive Indices
Birefringence
Optical Orientation
Pleochroism
Dispersion
Used Literature
[Steiger.etal:2008]Title: Crystallization of sodium sulfate phases in porous materials: The phase diagram Na2SO4–H2O and the generation of stress
Author: Steiger, Michael; Asmussen, Sönke
Link to Google Scholar


Abstract

Sodium sulfate phase III as a metastable and anhydrous phase of sodium sulfate and its properties are presented.

Occurence

The phase was observed next to thenardite during the evaporation of sodium sulfate solutions above 32.4 °C which is above the transition temperature of mirabilite to thenardite. The amount of metastable phase III increases with increasing temperature [Amirthalingam.etal:1977]Title: Topotaxic phase change in Na2SO4
Author: Amirthalingam V., Karkhanavala M. D., Rao U. R. K.
Link to Google Scholar
, [Grossi.etal:1997]Title: Acoustic emmission monitoring to study sodium sulphate crystallization in monumental porous carbonate stones
Author: Grossi, C.M.; Esbert, R.M.; Suarez del Rio, L.M.; Montoto, M.; Laurenzi-Tabasso, M.
Link to Google Scholar
.
In addition the phase was detected during evaporation tests with sodium sulfate solutions at room temperature and low relative humidity [Linnow.etal:2006]Title: Investigation of Sodium Sulfate Phase Transitions in a Porous Material Using Humidity- and Temperature-Controlled X-ray Diffraction
Author: Linnow, Kirsten; Zeunert, Anke; Steiger, Michael
Link to Google Scholar
, [Xu.etal:1999]Title: In-situ Raman observations of phase transformation of Na2SO4 during the hydration/dehydration cycles on single levitated microparticle.
Author: Xu B., Schweiger G.
Link to Google Scholar
, [Rodriguez-Navarro.etal:1999]Title: How does sodium sulphate crystallize?
Author: Rodriguez-Navarro, Carlos; Doehne, Eric
Link to Google Scholar
.

Solubility


Figure 1: Solubility of Na2SO4 in water, according to : [Steiger.etal:2008]Title: Crystallization of sodium sulfate phases in porous materials: The phase diagram Na2SO4–H2O and the generation of stress
Author: Steiger, Michael; Asmussen, Sönke
Link to Google Scholar



With a solubility of 4.4 mol/kg at 20 °C [Steiger.etal:2008]Title: Crystallization of sodium sulfate phases in porous materials: The phase diagram Na2SO4–H2O and the generation of stress
Author: Steiger, Michael; Asmussen, Sönke
Link to Google Scholar
phase III has got a higher solubility than the other phases of the system Na2SO4-H2O (see also sodium sulfate).

Hygroscopicity


Figure 2:Deliquescence of Na2SO4, according to: [Steiger.etal:2008]Title: Crystallization of sodium sulfate phases in porous materials: The phase diagram Na2SO4–H2O and the generation of stress
Author: Steiger, Michael; Asmussen, Sönke
Link to Google Scholar


The deliquescence humidity of phase III at 20 °C is 82.9 % and it slowly increases with increasing temperature.


Table 1: Deliquescence humidity of sodium sulfate phase III at different round temperatures, according to [Steiger.etal:2008]Title: Crystallization of sodium sulfate phases in porous materials: The phase diagram Na2SO4–H2O and the generation of stress
Author: Steiger, Michael; Asmussen, Sönke
Link to Google Scholar
0°C 10°C 20°C 30°C 40°C 50°C
79.9%r.h. 81.6%r.h. 82.9%r.h. 84.0%r.h. 84.9%r.h. 85.7%r.h.


Weblinks


Literatur

[Amirthalingam.etal:1977]Amirthalingam V., Karkhanavala M. D., Rao U. R. K. (1977): Topotaxic phase change in Na2SO4. Acta Cryst., (), 522Link to Google Scholar
[Grossi.etal:1997]Grossi, C.M.; Esbert, R.M.; Suarez del Rio, L.M.; Montoto, M.; Laurenzi-Tabasso, M. (1997): Acoustic emmission monitoring to study sodium sulphate crystallization in monumental porous carbonate stones. Studies in Conservation, (2), 115-125Link to Google Scholar
[Linnow.etal:2006]Linnow, Kirsten; Zeunert, Anke; Steiger, Michael (2006): Investigation of Sodium Sulfate Phase Transitions in a Porous Material Using Humidity- and Temperature-Controlled X-ray Diffraction. Analytical Chemistry, 78 (13), 4683-4689, 10.1021/ac0603936Link to Google Scholar
[Rodriguez-Navarro.etal:1999]Rodriguez-Navarro, Carlos; Doehne, Eric (2000): How does sodium sulphate crystallize?. Cement and Concrete Research, 30 (), 1527-1534, Url, 10.1016/S0008-8846(00)00381-1Link to Google Scholar
[Steiger.etal:2008]Steiger, Michael; Asmussen, Sönke (2008): Crystallization of sodium sulfate phases in porous materials: The phase diagram Na2SO4–H2O and the generation of stress. Geochimica et Cosmochimica Acta, 72 (17), 4291-4306, 10.1016/j.gca.2008.05.053Link to Google Scholar
[Xu.etal:1999]Xu B., Schweiger G. (1999): In-situ Raman observations of phase transformation of Na2SO4 during the hydration/dehydration cycles on single levitated microparticle.. J. Aerosol. Sci., (), 379-380Link to Google Scholar