Gypsum: Difference between revisions
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=== Solubility properties === | === Solubility properties === | ||
[[file:CaSO4 sol.JPG|thumb|350px| | [[file:CaSO4 sol.JPG|thumb|350px|left|'''Figure1:''' Solubility of CaSO4 in water (diagram: Michael Steiger)]] | ||
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<br>Gips zählt zur Gruppe der "gering" wasserlöslichen Salze und kann somit als wenig mobil bezeichnet werden. Allerdings ist der Fremdioneneinfluss auf die Gipslöslichkeit vergleichsweise groß. So wird die Löslichkeit von Gips durch Halit je nach Konzentrationsverhältnis bis um den Faktor vier erhöht.<br> | <br>Gips zählt zur Gruppe der "gering" wasserlöslichen Salze und kann somit als wenig mobil bezeichnet werden. Allerdings ist der Fremdioneneinfluss auf die Gipslöslichkeit vergleichsweise groß. So wird die Löslichkeit von Gips durch Halit je nach Konzentrationsverhältnis bis um den Faktor vier erhöht.<br> | ||
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[[file:Loeslichkeit Gips 02.JPG|thumb| | [[file:Loeslichkeit Gips 02.JPG|thumb|left|350px|'''Figure 2:'''Solubility of gipsum compared with other salte (after <bib id=Stark.etal:1996/>)]] | ||
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=== Hydratationsverhalten === | === Hydratationsverhalten === | ||
Revision as of 16:29, 26 December 2011
<bibimport/>
| Gypsum[1][2] | |
| |
| Mineralogical name | Gypsum, Selenite |
| Chemical name | Calcium sulfate dihydrate |
| Trivial name | Gypsite, Sulfate of Lime |
| Chemical formula | Ca[SO4]•2H2O |
| Other forms | Anhydrite (CaSO4) Hemihydrate (CaSO4•0.5H2O) |
| Crystal system | monoclinic |
| Crystal structure | |
| Deliquescence humidity 20°C | |
| Solubility (g/l) at 20°C | 2.14 g/l |
| Density (g/cm³) | 2.2-2.4 g/cm³ |
| Molar volume | 74.69 cm3/mol |
| Molar weight | 172.17g /mol |
| Transparency | transparent to opaque |
| Cleavage | perfect |
| Crystal habit | |
| Twinning | |
| Phase transition | |
| Chemical behavior | |
| Comments | hardly soluble in water |
| Crystal Optics | |
| Refractive Indices | α = 1.519-1.521 β = 1.522-1.523 γ = 1.529-1.530 |
| Birefringence | Δ = 0.010 |
| Optical Orientation | biaxial positive |
| Pleochroism | |
| Dispersion | 58° |
| Used Literature | |
| {{{Literature}}} | |
Authors: Hans-Jürgen Schwarz , Nils Mainusch, Tim Müller
back to Sulfate
Calciumsulfate and Gipsum[edit]
Solubility properties[edit]
Author: Stark, Jochen; Stürmer, Sylvia
)Photos of gypsum crystals and deterioration pattern caused by gypsum[edit]
On a object[edit]
Salt damage on a brick, St. Jakobi Church, Perleberg
-Ausschnitt.jpg)
Under the polarising microscope[edit]
- In thin section of bricks
Brick with gypsum caused damage, St. Jakobi Church, Perleberg, Germany
Brick with gypsum caused damage, St. Jakobi Church, Perleberg, Germany
Gypsum crystals between plaster layers
- Gypsum crystallized out of a solution in water on a glass slide
Calcium sulfate crystallized out of a solution in water on a glass slide
Calcium sulfate with sodium chloride of a real sample, Gypsum crystallized out of a solution in water on a glass slide
Calcium sulfate with sodium chloride of a real sample, Gypsum crystallized out of a solution in water on a glass slide
Calcium sulfate, Gypsum crystallized out of a solution in water on a glass slide
Under the Scanning Electron Microscope (SEM)[edit]
- In a SEM
Gypsum crystals in a SEM
Gypsum crystals in a SEM
Gypsum crystals in a SEM
EDX spektra of gypsum crystals in a SEM
Gypsum crystals in a SEM
Gypsum crystals in a SEM
Gypsum crystals in a SEM
EDX spektra of gypsum crystals in a SEM
Weblinks[edit]
- ↑ http://webmineral.com/data/Gypsum.shtml seen on 30.07.2010
- ↑ http://www.mindat.org/min-1784.html seen on 30.07.2010
Literatur[edit]
[Filter missing]