Magnesium sulfate

Magnesium sulfate ;
Names:	magnesium sulfate; magnesium(II) sulfate; Epsom salt; english salt; bitter salt; bath salt;
Formula:	MgSO4 (anhydrous); MgSO4 · 7H2O (heptahydrate);
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, b=12.013 Å, c=6.861 Åα=90°, β=90°, γ=90°; orthorhombic (α-anhydrous); a=5.174713 Å, b=7.87563 Å, c=6.49517 Åα=90°, β=90°, γ=90°; orthorhombic (β-anhydrous); a=4.74599 Å, b=8.5831 Å, c=6.70934 Åα=90°, β=90°, γ=90°; monoclinic (monohydrate, kieserite); a=6.891 Å, b=7.624 Å, c=7.645 Åα=90°, β=117.683°, γ=90°; orthorhombic (dihydrate, sanderite); a=8.8932 Å, b=8.4881 Å, c=12.4401 Åα=90°, β=90°, γ=90°; monoclinic (tetrahydrate, starkeyite); a=5.922 Å, b=13.604 Å, c=7.905 Åα=90°, β=90.85°, γ=90°; monoclinic (tetrahydrate, cranswickite); a=11.9236 Å, b=5.1736 Å, c=12.1958 Åα=90°, β=117.548°, γ=90°; triclinic (pentahydrate, pentahydrite); a=6.314 Å, b=10.505 Å, c=6.03 Åα=81.12°, β=109.82°, γ=105.08°; monoclinic (hexahydrate, hexahydrite); a=9.975 Å, b=7.186 Å, c=24.267 Åα=90°, β=98.78°, γ=90°; monoclinic (monodecahydrate, meridianiite); a=6.72548 Å, b=6.77937 Å, c=17.2898 Åα=90°, β=89.478°, γ=90°;
Shapes:	https://en.crystalls.info/w/uploads/media/2/28/Prolongated_tetragonal_pyramidal_prism.json Prolongated tetragonal pyramidal prism https://en.crystalls.info/w/uploads/media/5/50/Beveled_tetragonal_prism.json Beveled tetragonal prism https://en.crystalls.info/w/uploads/media/a/af/Tetragonal_prism.json Tetragonal prism https://en.crystalls.info/w/uploads/media/2/2f/Prolongated_octahedron.json Prolongated octahedron https://en.crystalls.info/w/uploads/media/9/9e/Truncated_tetragonal_prism.json Truncated tetragonal prism https://en.crystalls.info/w/uploads/media/5/52/Needle.json Needle ;
Color:	colorless; white;
Decomposition point:	1127 °C1,400.15 K <br />2,060.6 °F <br />2,520.27 °R <br /> (anhydrous); 194 °C467.15 K <br />381.2 °F <br />840.87 °R <br /> (monohydrate); 73 °C346.15 K <br />163.4 °F <br />623.07 °R <br /> (hexahydrate); 48.4 °C321.55 K <br />119.12 °F <br />578.79 °R <br /> (heptahydrate); -2 °C271.15 K <br />28.4 °F <br />488.07 °R <br /> (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

Can be bought 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

heptahydrateheptahydrate
anhydrous

а 23.66g of hydroxide or 34.21g of carbonate or 34.21g of magnesium oxide and 107.55g of 37%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

heptahydrateheptahydrate
anhydrous

а 9.86g of magnesium and 107.55g of 37%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

heptahydrateheptahydrate
anhydrous

а 9.86g of magnesium and 101.30g of copper(II) sulfate

pentahydratepentahydrate
anhydrous

or 112.80g of iron(II) sulfate

heptahydrateheptahydrate
tetrahydrate
anhydrous

or 116.67g of zinc sulfate

heptahydrateheptahydrate
hexahydrate
monohydrate
anhydrous

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

Influence of solution temperature on crystal shape of magnesium sulfateMagnesium sulfate

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

TableGraph

Temperature	гр/`100,00` гр water		гр/`100,00` гр ethanol		гр/`100,00` гр methanol		гр/`100,00` гр diethyl ether	гр/`100,00` гр glycerol	гр/`100,00` гр formic acid 95%	гр/`100,00` гр sulfuric acid
Temperature	(anhydrous)	(heptahydrate)	(anhydrous)	(heptahydrate)	(anhydrous)	(heptahydrate)	(anhydrous)	(anhydrous)	(anhydrous)	(anhydrous)
0°C273.15 K <br />32 °F <br />491.67 °R <br />	`25.5`			`1.3`		`29`
10°C283.15 K <br />50 °F <br />509.67 °R <br />	`30.4`
15°C288.15 K <br />59 °F <br />518.67 °R <br />			`0.025`		`0.276`
20°C293.15 K <br />68 °F <br />527.67 °R <br />	`35.1`	`71`					`1.16`		`0.34`
25°C298.15 K <br />77 °F <br />536.67 °R <br />	`37.4`				`0.224`			`26.3`		`0.22`
30°C303.15 K <br />86 °F <br />545.67 °R <br />	`39.7`
40°C313.15 K <br />104 °F <br />563.67 °R <br />	`44.7`					`41`
50°C323.15 K <br />122 °F <br />581.67 °R <br />	`50.4`
60°C333.15 K <br />140 °F <br />599.67 °R <br />	`54.8`		`0.016`		`0.0123`
70°C343.15 K <br />158 °F <br />617.67 °R <br />	`59.2`
80°C353.15 K <br />176 °F <br />635.67 °R <br />	`54.8`
90°C363.15 K <br />194 °F <br />653.67 °R <br />										`1.71`
100°C373.15 K <br />212 °F <br />671.67 °R <br />	`50.2`

Insoluble in acetone, carbon disulfide, ethyl acetate, methyl acetate and ammonia.

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Magnesium compounds
Salts	Magnesium hydrocarbonate (Mg(HCO₃)₂) • Magnesium sulfamate (Mg(NH₂SO₃)₂) • Magnesium sulfate (MgSO₄)
Double salts	Iron(II)-magnesium sulfate ((Fe,Mg)SO₄) • Magnesium-ammonium sulfate ((NH₄)₂MgSO₄) • Magnesium-potassium sulfate (K₂MgSO₄) • Magnesium-potassium sulfate-chromate (K₂CrO₄ · MgSO₄)

Sulfates
Simple	Aluminum sulfate (Al₂(SO₄)₃) • Ammonium sulfate ((NH₄)₂SO₄) • Calcium sulfate (CaSO₄) • Cadmium sulfate (CdSO₄) • Cerium(III) sulfate (Ce₂(SO₄)₃) • Cerium(IV) sulfate (Ce(SO₄)₂) • Chromium(III) sulfate (Cr₂(SO₄)₃) • Cobalt(II) sulfate (CoSO₄) • Copper(II) sulfate (CuSO₄) • Gadolinium sulfate (Gd₂(SO₄)₃) • Holmium sulfate (Ho₂(SO₄)₃) • Hydrazine sulfate (N₂H₄ · H₂SO₄) • Iron(II) sulfate (FeSO₄) • Iron(III) sulfate (Fe₂(SO₄)₃) • Lanthanum sulfate (La₂(SO₄)₃) • Lithium sulfate (Li₂SO₄) • Magnesium sulfate (MgSO₄) • Manganese(II) sulfate (MnSO₄) • Neodymium sulfate (Nd₂(SO₄)₃) • Nickel sulfate (NiSO₄) • Potassium sulfate (K₂SO₄) • Praseodymium(III) sulfate (Pr₂(SO₄)₃) • Rubidium sulfate (Rb₂SO₄) • Sodium hydrosulfate (NaHSO₄) • Sodium sulfate (Na₂SO₄) • Yttrium sulfate (Gd₂(SO₄)₃) • Zinc sulfate (ZnSO₄)
Alums	Aluminum-ammonium sulfate (NH₄Al(SO₄)₂) • Aluminum-potassium sulfate (KAl(SO₄)₂) • Chromium(III)-ammonium sulfate (NH₄Cr(SO₄)₂) • Chromium(III)-potassium sulfate (KCr(SO₄)₂) • Cobalt(III)-ammonium sulfate (NH₄Co(SO₄)₂) • Indium(III)-potassium sulfate (KIn(SO₄)₂) • Iron(III)-ammonium sulfate (NH₄Fe(SO₄)₂) • Iron(III)-potassium sulfate (KFe(SO₄)₂) • Manganese(III)-ammonium sulfate (NH₄Mn(SO₄)₂) • Vanadium(III)-ammonium sulfate (NH₄V(SO₄)₂)
Tutton's salts	Chromium(II)-ammonium sulfate ((NH₄)₂Cr(SO₄)₂) • Cobalt(II)-ammonium sulfate ((NH₄)₂Co(SO₄)₂) • Cobalt(II)-potassium sulfate (K₂Co(SO₄)₂) • Copper(II)-ammonium sulfate ((NH₄)₂Cu(SO₄)₂) • Copper(II)-potassium sulfate (K₂Cu(SO₄)₂) • Iron(II)-ammonium sulfate ((NH₄)₂Fe(SO₄)₂) • Iron(II)-potassium sulfate (K₂Fe(SO₄)₂) • Magnesium-ammonium sulfate ((NH₄)₂Mg(SO₄)₂) • Magnesium-potassium sulfate (K₂Mg(SO₄)₂) • Magnesium-potassium sulfate-chromate (K₂CrO₄ · MgSO₄) • Manganese(II)-ammonium sulfate ((NH₄)₂Mn(SO₄)₂) • Manganese(II)-potassium sulfate (K₂Mn(SO₄)₂) • Nickel-ammonium sulfate ((NH₄)₂Ni(SO₄)₂) • Nickel-potassium sulfate (K₂Ni(SO₄)₂) • Vanadium(II)-ammonium sulfate ((NH₄)₂V(SO₄)₂) • Zinc-ammonium sulfate ((NH₄)₂Zn(SO₄)₂) • Zinc-potassium sulfate (K₂Zn(SO₄)₂) •
Double salts	Copper(II)-iron(II) sulfate ((Cu,Fe)SO₄) • Iron(II)-magnesium sulfate ((Fe,Mg)SO₄) • Lithium-potassium sulfate (KLiSO₄) • Sodium-ammonium sulfate (NaNH₄SO₄) • Zinc-sodium sulfate (Na₂Zn(SO₄)₂) •
Adducts	Triglycine sulfate ((NH₂CH₂COOH)₃ · H₂SO₄) • Glutamic acid sulfate (C₅H₉NO₄ · H₂SO₄)
Complexes	Cerium(III) sulfocerate(IV) (Ce₄[Ce(SO₄)₄]₃) • Glycinecopper(II) sulfate ([Cu(NH₂CH₂COOH)]SO₄) • Hexakarbamatzinc sulfate ([(CON₂H₄)₆Zn]SO₄) • Tetraamminecopper(II) sulfate ([Cu(NH₃)₄]SO₄) • Tris(hydroxymethil)methanoaminecopper(II) sulfate ([Cu(NH₂C(CH₂OH)₃)₄]SO₄)

Magnesium sulfate
Names:	magnesium sulfate magnesium(II) sulfate Epsom salt english salt bitter salt bath salt
Formula:	MgSO₄ (anhydrous) MgSO₄ · 7H₂O (heptahydrate)
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, b=12.013 Å, c=6.861 Åα=90°, β=90°, γ=90° orthorhombic (α-anhydrous) a=5.174713 Å, b=7.87563 Å, c=6.49517 Åα=90°, β=90°, γ=90° orthorhombic (β-anhydrous) a=4.74599 Å, b=8.5831 Å, c=6.70934 Åα=90°, β=90°, γ=90° monoclinic (monohydrate, kieserite) a=6.891 Å, b=7.624 Å, c=7.645 Åα=90°, β=117.683°, γ=90° orthorhombic (dihydrate, sanderite) a=8.8932 Å, b=8.4881 Å, c=12.4401 Åα=90°, β=90°, γ=90° monoclinic (tetrahydrate, starkeyite) a=5.922 Å, b=13.604 Å, c=7.905 Åα=90°, β=90.85°, γ=90° monoclinic (tetrahydrate, cranswickite) a=11.9236 Å, b=5.1736 Å, c=12.1958 Åα=90°, β=117.548°, γ=90° triclinic (pentahydrate, pentahydrite) a=6.314 Å, b=10.505 Å, c=6.03 Åα=81.12°, β=109.82°, γ=105.08° monoclinic (hexahydrate, hexahydrite) a=9.975 Å, b=7.186 Å, c=24.267 Åα=90°, β=98.78°, γ=90° monoclinic (monodecahydrate, meridianiite) a=6.72548 Å, b=6.77937 Å, c=17.2898 Åα=90°, β=89.478°, γ=90°
Shapes:	Prolongated tetragonal pyramidal prism Beveled tetragonal prism Tetragonal prism Prolongated octahedron Truncated tetragonal prism Needle
Color:	colorless white
Decomposition point:	1127 °C1,400.15 K <br />2,060.6 °F <br />2,520.27 °R <br /> (anhydrous) 194 °C467.15 K <br />381.2 °F <br />840.87 °R <br /> (monohydrate) 73 °C346.15 K <br />163.4 °F <br />623.07 °R <br /> (hexahydrate) 48.4 °C321.55 K <br />119.12 °F <br />578.79 °R <br /> (heptahydrate) -2 °C271.15 K <br />28.4 °F <br />488.07 °R <br /> (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