Magnesium sulfate

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  Magnesium sulfate   
Names: magnesium sulfate
magnesium(II) sulfate
Epsom salt
english salt
bitter salt

Formula: MgSO4 (anhydrous)
MgSO4 · 7H2O (heptahydrate)
SMILES: [O-]S(=O)(=O)[O-].[Mg+2]
Molar mass: 120.366 g/mol (anhydrous)
246.470 g/mol (heptahydrate)
Density: 2.66 g/cm3 (anhydrous)
2.445 g/cm3 (monohydrate)
1.68 g/cm3 (heptahydrate)
Crystal system: orthorhombic (heptahydrate, epsomite)
a=11.887 Å
11.8870 Å
1.1887 nm
, b=12.013 Å
12.0130 Å
1.2013 nm
, c=6.861 Å
6.8610 Å
0.6861 nm
α=90°
90°  
, β=90°
90°  
, γ=90°
90°  

orthorhombic (α-anhydrous)
a=5.174713 Å
5.1747 Å
0.5175 nm
, b=7.87563 Å
7.8756 Å
0.7876 nm
, c=6.49517 Å
6.4952 Å
0.6495 nm
α=90°
90°  
, β=90°
90°  
, γ=90°
90°  

orthorhombic (β-anhydrous)
a=4.74599 Å
4.7460 Å
0.4746 nm
, b=8.5831 Å
8.5831 Å
0.8583 nm
, c=6.70934 Å
6.7093 Å
0.6709 nm
α=90°
90°  
, β=90°
90°  
, γ=90°
90°  

monoclinic (monohydrate, kieserite)
a=6.891 Å
6.8910 Å
0.6891 nm
, b=7.624 Å
7.6240 Å
0.7624 nm
, c=7.645 Å
7.6450 Å
0.7645 nm
α=90°
90°  
, β=117.683°
117°40′58.8″  
, γ=90°
90°  

orthorhombic (dihydrate, sanderite)
a=8.8932 Å
8.8932 Å
0.8893 nm
, b=8.4881 Å
8.4881 Å
0.8488 nm
, c=12.4401 Å
12.4401 Å
1.2440 nm
α=90°
90°  
, β=90°
90°  
, γ=90°
90°  

monoclinic (tetrahydrate, starkeyite)
a=5.922 Å
5.9220 Å
0.5922 nm
, b=13.604 Å
13.6040 Å
1.3604 nm
, c=7.905 Å
7.9050 Å
0.7905 nm
α=90°
90°  
, β=90.85°
90°50′60.0″  
, γ=90°
90°  

monoclinic (tetrahydrate, cranswickite)
a=11.9236 Å
11.9236 Å
1.1924 nm
, b=5.1736 Å
5.1736 Å
0.5174 nm
, c=12.1958 Å
12.1958 Å
1.2196 nm
α=90°
90°  
, β=117.548°
117°32′52.8″  
, γ=90°
90°  

triclinic (pentahydrate, pentahydrite)
a=6.314 Å
6.3140 Å
0.6314 nm
, b=10.505 Å
10.5050 Å
1.0505 nm
, c=6.03 Å
6.0300 Å
0.6030 nm
α=81.12°
81°7′12.0″  
, β=109.82°
109°49′12.0″  
, γ=105.08°
105°4′48.0″  

monoclinic (hexahydrate, hexahydrite)
a=9.975 Å
9.9750 Å
0.9975 nm
, b=7.186 Å
7.1860 Å
0.7186 nm
, c=24.267 Å
24.2670 Å
2.4267 nm
α=90°
90°  
, β=98.78°
98°46′48.0″  
, γ=90°
90°  

monoclinic (monodecahydrate, meridianiite)
a=6.72548 Å
6.7255 Å
0.6725 nm
, b=6.77937 Å
6.7794 Å
0.6779 nm
, c=17.2898 Å
17.2898 Å
1.7290 nm
α=90°
90°  
, β=89.478°
89°28′40.8″  
, γ=90°
90°  

Shapes:
https://media.crystalls.info/w/uploads/media/Prolongated_tetragonal_pyramidal_prism.json
https://media.crystalls.info/w/uploads/media/Beveled_tetragonal_prism.json
https://media.crystalls.info/w/uploads/media/Tetragonal_prism.json
https://media.crystalls.info/w/uploads/media/Prolongated_octahedron.json
https://media.crystalls.info/w/uploads/media/Truncated_tetragonal_prism.json
https://media.crystalls.info/w/uploads/media/Needle.json

Color: colorless
white
Decomposition point: 1127 °C
1,400.15 K
2,060.6 °F
2,520.27 °R
(anhydrous)
194 °C
467.15 K
381.2 °F
840.87 °R
(monohydrate)
73 °C
346.15 K
163.4 °F
623.07 °R
(hexahydrate)
48.4 °C
321.55 K
119.12 °F
578.79 °R
(heptahydrate)
-2 °C
271.15 K
28.4 °F
488.07 °R
(monodecahydrate)
Refractive index: 1.523 (monohydrate)
1.433 (heptahydrate)
Magnetic properties: diamagnetic
χ=-5.00 · 10-5cm³/mol
Stability: strongly erodes (heptahydrate)
hygroscopic (anhydrous)
Hardness: relatively strong
(2 on Moh`s scale)
Toxicity: slightly toxic
LD50=1200mg/kg

Description

Inorganic compound, salt of bivalent transitional metal magnesium and inorganic sulfuric acid. From water solutions crystallizes as heptahydrate.

Minerals

Occurs in nature as epsomite, kieserite, sanderite, starkeyite, cranswickite, pentahydrite, hexahydrite and meridianiite minerals.

Where to buy

In pharmacy (as "Magnesium sulfate" or "Epsom salt").

Precursors

Reaction between hydroxide, carbonate or magnesium oxide and sulfuric acid

Chemical equation:

H2SO4 + Mg(OH)2 = MgSO4 + 2H2O
H2SO4 + MgCO3 = MgSO4 + H2O + CO2
H2SO4 + MgO = MgSO4 + H2O

For preparation of 100.00g of magnesium sulfate heptahydrate а 23.66g of hydroxide or 34.21g of carbonate or 34.21g of magnesium oxide and 107.55g of 37% sulfuric acid is required.
Add acid to the flask, then add small parts of magnesium compound with stirring until it will totally dissolve or, if you use carbonate, until carbon dioxide emission will stop. After reaction will stop, filter the solution and use it for crystal growing.

Reaction between metal magnesium and sulfuric acid

Chemical equation:

H2SO4 + Mg = MgSO4 + H2

For preparation of 100.00g of magnesium sulfate heptahydrate а 9.86g of magnesium and 107.55g of 37% sulfuric acid is required.
Add diluted acid solution to the flask, then add magnesium pieces, shavings or powder and stir it until gas emission will stop.

Reaction between metal magnesium and copper(II), zinc or iron sulfate

Chemical equation:

CuSO4 + Mg = MgSO4 + Cu↓
ZnSO4 + Mg = MgSO4 + Zn↓
FeSO4 + Mg = MgSO4 + Fe↓

For preparation of 100.00g of magnesium sulfate heptahydrate а 9.86g of magnesium and 101.30g of copper(II) sulfate pentahydrate or 112.80g of iron(II) sulfate heptahydrate or 116.67g of zinc sulfate heptahydrate is required.
Add copper, iron or zinc sulfate solution to the flask, then add magnesium pieces, shavings or powder and leave for a few days. After solution color changing will stop, less active metal will completely displace into the precipitate. Then filter the solution.

Influence of temperature

Storage conditions

For crystal storing use hermetic vessel with small amount of saturated solution at the bottom or place wadding moistened with such solution. You can use such alternatives as vessel with vaseline or vegetable oil, organic non-hygroscopic solvent (kerosene, benzine or paraffin). Also you can use acrylate polymer or another kinds of solidifying plastic.

Solubility

Temperatureгр/100,00 гр waterгр/100,00 гр ethanolгр/100,00 гр methanolгр/100,00 гр diethyl etherгр/100,00 гр glycerolгр/100,00 гр formic acid 95%гр/100,00 гр sulfuric acid
(anhydrous)(heptahydrate)(anhydrous)(heptahydrate)(anhydrous)(heptahydrate)(anhydrous)(anhydrous)(anhydrous)(anhydrous)
0°C
273.15 K
32 °F
491.67 °R
25.5
25.5 g/100g
20.319 %
1.3
1.3 g/100g
1.283 %
29
29 g/100g
22.481 %
10°C
283.15 K
50 °F
509.67 °R
30.4
30.4 g/100g
23.313 %
15°C
288.15 K
59 °F
518.67 °R
~32.8
32.8 g/100g
24.699 %
0.025
0.025 g/100g
0.025 %
0.276
0.276 g/100g
0.275 %
20°C
293.15 K
68 °F
527.67 °R
35.1
35.1 g/100g
25.981 %
71
71 g/100g
41.52 %
~0.25
0.25 g/100g
0.249 %
1.16
1.16 g/100g
1.147 %
0.34
0.34 g/100g
0.339 %
25°C
298.15 K
77 °F
536.67 °R
37.4
37.4 g/100g
27.22 %
0.224
0.224 g/100g
0.223 %
26.3
26.3 g/100g
20.823 %
0.22
0.22 g/100g
0.22 %
30°C
303.15 K
86 °F
545.67 °R
39.7
39.7 g/100g
28.418 %
~0.19
0.19 g/100g
0.19 %
40°C
313.15 K
104 °F
563.67 °R
44.7
44.7 g/100g
30.891 %
~0.13
0.13 g/100g
0.13 %
41
41 g/100g
29.078 %
50°C
323.15 K
122 °F
581.67 °R
50.4
50.4 g/100g
33.511 %
~0.07
0.07 g/100g
0.07 %
60°C
333.15 K
140 °F
599.67 °R
54.8
54.8 g/100g
35.401 %
0.016
0.016 g/100g
0.016 %
0.0123
0.0123 g/100g
0.0123 %
70°C
343.15 K
158 °F
617.67 °R
59.2
59.2 g/100g
37.186 %
80°C
353.15 K
176 °F
635.67 °R
54.8
54.8 g/100g
35.401 %
90°C
363.15 K
194 °F
653.67 °R
~52.5
52.5 g/100g
34.426 %
1.71
1.71 g/100g
1.681 %
100°C
373.15 K
212 °F
671.67 °R
50.2
50.2 g/100g
33.422 %
Insoluble in acetone, carbon disulfide, ethyl acetate, methyl acetate and ammonia.

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