Epsomite

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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
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Hygroscopicity[edit]

Figure 1: The system MgSO4/H2 form -30°C to 80°C , (Diagram: Michael Steiger)


Table 1:Deliquescence points at different temperatures [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 [Vogt.etal:1993]Title: Der Einfluss hygroskopischer Salze auf die Gleichgewichtsfeuchte und Trocknung anorganischer Baustoffe
Author: Vogt, R.; Goretzki, Lothar
Link to Google Scholar
]
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]

On objects[edit]

Under the polarising microscope[edit]


Weblinks[edit]