Epsomite: Difference between revisions

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== Hygroskopicity ==
== Hygroscopicity ==
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Die geringe Hygroskopizität des Reinsalzes Epsomit, die in dem hohen Wert der Gleichgewichtsfeuchte im Bereich 88-90 % r.F. deutlich wird, kann nicht isoliert betrachtet werden. In Mischsystemen, d.h. unter dem Einfluss von Fremdionen, liegt der Sorptionspunkt tiefer (siehe Tab.). Die Möglichkeit der hygroskopischen Feuchteaufnahme mit den damit verbundenen Problematiken ist trotz des hohen Deliqueszenzpunktes durchaus gegeben. <br>
Die geringe Hygroskopizität des Reinsalzes Epsomit, die in dem hohen Wert der Gleichgewichtsfeuchte im Bereich 88-90 % r.F. deutlich wird, kann nicht isoliert betrachtet werden. In Mischsystemen, d.h. unter dem Einfluss von Fremdionen, liegt der Sorptionspunkt tiefer (siehe Tab.). Die Möglichkeit der hygroskopischen Feuchteaufnahme mit den damit verbundenen Problematiken ist trotz des hohen Deliqueszenzpunktes durchaus gegeben. <br>
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[[file:MgSO4_a.jpg|thumb|350px|right|'''Fifure 2:''' The system MgSO<sub>4</sub>/H<sub>2</sub> form -30°C to 80°C , (Diagram: Michael Steiger)]]
[[file:MgSO4_a.jpg|thumb|350px|right|'''Figure 2:''' The system MgSO<sub>4</sub>/H<sub>2</sub> form -30°C to 80°C , (Diagram: Michael Steiger)]]


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{|border="2" cellspacing="0" cellpadding="4" width="52%" align="left" class="wikitable"
{|border="2" cellspacing="0" cellpadding="4" width="52%" align="left" class="wikitable"
|+''Tabelle 1:Deliqueszenzpunkte in Abhängigkeit zur Temperatur [nach <bib id=Arnold.etal:1991/>]''                    <!-- Tabellenüberschrift einfügen -->
|+''Table 1:Deliqueszenz points and temperature [after <bib id=Arnold.etal:1991/>]''                    <!-- Tabellenüberschrift einfügen -->
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|bgcolor = "#F0F0F0" align=center| 10°C  
|bgcolor = "#F0F0F0" align=center| 10°C  
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|bgcolor = "#FFFFEO" align=center| 88,3% r.F.  
|bgcolor = "#FFFFEO" align=center| 88,3% r.F.  
|bgcolor = "#FFFFEO" align=center| 88,0% r.F.
|bgcolor = "#FFFFEO" align=center| 88,0% r.F.
|}
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{|border="2" cellspacing="0" cellpadding="4" width="52%" align="left" class="wikitable"
|+''Tabelle 2: Gleichgewichtsfeuchte im Salzgemisch (Mischungsverhältnis: Gesättigte Lsg. A/ gesättigte Lsg. B =1:1) [nach <bib id=Vogt.etal:1993/>]''   
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|bgcolor = "#F0F0F0" align=center|
|bgcolor = "#F0F0F0" align=center| '''Ca(NO<sub>3</sub>)<sub>2</sub>'''
|bgcolor = "#F0F0F0" align=center| '''KNO<sub>3</sub>'''
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|bgcolor = "#FFFFEO" align=center|  '''MgSO<sub>4</sub> xH<sub>2</sub>O'''
|bgcolor = "#FFFFEO" align=center|  67 (21°C)
|bgcolor = "#FFFFEO" align=center|  78(21°C)
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===Feuchtesorption===
===Sorption of moisture===
{|border="2" cellspacing="0" cellpadding="4" width="52%" align="left" class="wikitable sortable"
{|border="2" cellspacing="0" cellpadding="4" width="52%" align="left" class="wikitable sortable"
|+''Tabelle 3:Sorptionsverhalten von Magnesiumsulfat [nach <bib id=Vogt.etal:1993/>]''
|+''Tabele 2: Behavior concerning moisture sorption of magnesium sulfate [after bib id=Vogt.etal:1993/>]''
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|bgcolor = "#F0F0F0"| '''Lagerungsfeuchte'''  
|bgcolor = "#F0F0F0"| '''Moisture sorption at'''  
|bgcolor = "#F0F0F0"| '''87%r.F.'''  
|bgcolor = "#F0F0F0"| '''87%r.F.'''  
|bgcolor = "#F0F0F0"| '''81%r.F.'''  
|bgcolor = "#F0F0F0"| '''81%r.F.'''  
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|bgcolor = "#FFFFEO" align=center| 27
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|bgcolor = "#F7F7F7"| '''MgSO<sub>4</sub> + NaCl'''<br>(1:1 molare Mischung)  
|bgcolor = "#F7F7F7"| '''MgSO<sub>4</sub> + NaCl'''<br>(1:1 molare mixture)  
|bgcolor = "#FFFFEO" align=center| 240  
|bgcolor = "#FFFFEO" align=center| 240  
|bgcolor = "#FFFFEO" align=center| 146  
|bgcolor = "#FFFFEO" align=center| 146  

Revision as of 15:54, 26 December 2011

Epsomite[1][2]
HJS MgSO4 092503-2.jpg
Mineralogical name Epsomite
Chemical name Magnesiumsulfate Heptahydrate
Trivial name Bitter Salts, Reichardtite, Seelandite
Chemical formula MgSO4•7H2O
Other forms Kieserite (MgSO4•H2O)
Sanderite (MgSO4•2H2O)
Starkeyite (MgSO4•4H2O)
Pentahydrite(MgSO4•5H2O)
Hexahydrite (MgSO4•6H2O)
Meridianite (MgSO4•11H2O)
Magnesium 12-Hydrate
Crystal system orthorhombic
Crystal structure
Deliquescence humidity 20°C 90.1% (20°C), 94% (30°C)
Solubility (g/l) at 20°C 710 g/l
Density (g/cm³) 146.8 cm3/mol
Molar volume 246.48 g/mol
Molar weight 1.67 g/cm3
Transparency transparent to translucent
Cleavage perfect
Crystal habit
Twinning
Phase transition
Chemical behavior
Comments can by produced from an aqueous solution under 50°C
Crystal Optics
Refractive Indices nx = 1.433
ny = 1.455
nz = 1.461
Birefringence Δ = 0.028
Optical Orientation biaxial negative
Pleochroism
Dispersion
Used Literature
{{{Literature}}}


<bibimport/> Authors: Hans-Jürgen Schwarz, Tim Müller, Nils Mainusch
back to Sulfate

Hygroscopicity[edit]

Figure 2: The system MgSO4/H2 form -30°C to 80°C , (Diagram: Michael Steiger)


Table 1:Deliqueszenz points and temperature [after [Arnold.etal:1991]Title: Monitoring Wall Paintings Affected by soluble Salts
Author: Arnold, Andreas; Zehnder, Konrad
Link to Google Scholar]
10°C 20°C 25°C 30°C
86,9% r.F. 90,1% r.F. 88,3% r.F. 88,0% r.F.


Sorption of moisture[edit]

Tabele 2: Behavior concerning moisture sorption of magnesium sulfate [after bib id=Vogt.etal:1993/>]
Moisture sorption at 87%r.F. 81%r.F. 70%r.F. 61%r.F. 50%r.F.
MgSO4 76 75 70 71 27
MgSO4 + NaCl
(1:1 molare mixture) 		240 146 75 50 20


Salts and deteriation pattern[edit]

t the objects[edit]

Under the polarizing microscope[edit]

  • Crystallized from a water solution on a glass slide
  • Sampole of a salt crust of magnesium sulfate whiskers

    Sampole of a salt crust of magnesium sulfate whiskers

  • Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

    Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

  • Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

    Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

  • Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

    Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

  • Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

    Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

  • Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

    Real sample with magnesium sulfate salts, crystallized from a water solution on a glass slide

  • Kieserite-crystals

    Kieserite-crystals

  • Kieserite-crystals

    Kieserite-crystals

  • Kieserite-crystals

    Kieserite-crystals

  • Kieserite-crystals

    Kieserite-crystals

  • Kieserite-crystals

    Kieserite-crystals

  • Kieserite-crystals

    Kieserite-crystals

  • Magnesium- ulfate, crystallized from a water solution on a glass slide

    Magnesium- ulfate, crystallized from a water solution on a glass slide

  • Magnesium sulfate, crystallized from a water solution on a glass slide

    Magnesium sulfate, crystallized from a water solution on a glass slide

  • Magnesium sulfate, crystallized from a water solution on a glass slide

    Magnesium sulfate, crystallized from a water solution on a glass slide

  • Magnesium sulfate, crystallized from a water solution on a glass slide

    Magnesium sulfate, crystallized from a water solution on a glass slide

  • Magnesium sulfate, crystallized from a water solution on a glass slide

    Magnesium sulfate, crystallized from a water solution on a glass slide

  • Magnesium sulfate, crystallized from a water solution on a glass slide

    Magnesium sulfate, crystallized from a water solution on a glass slide

  • Magnesium sulfate, crystallized from a water solution on a glass slide

    Magnesium sulfate, crystallized from a water solution on a glass slide

  • Magnesium sulfate, crystallized from a water solution on a glass slide

    Magnesium sulfate, crystallized from a water solution on a glass slide


Weblinks[edit]

  1. ↑ http://webmineral.com/data/Epsomite.shtml seen on 29.072010
  2. ↑ http://www.mindat.org/min-1393.html seen on 29.072010

A phase is a physically distinctive form of matter and is characterized by having relatively uniform chemical and physical properties.

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