Iron(II) sulfate

Iron(II) sulfate ;
Names:	ferrous sulfate; iron vitriol; green vitriol;
Formula:	FeSO4 (anhydrous); FeSO4 · 4H2O (tetrahydrate); FeSO4 · 7H2O (heptahydrate);
Molar mass:	151.906 g/mol (anhydrous); 223.966 g/mol (tetrahydrate); 278.010 g/mol (heptahydrate);
Density:	3.56 g/cm3 (anhydrous); 3 g/cm3 (monohydrate); 2.15 g/cm3 (tetrahydrate); 1.898 g/cm3 (heptahydrate);
Crystal system:	orthorhombic (anhydrous); a=8.7042 Å, b=6.8013 Å, c=4.7868 Åα=90°, β=90°, γ=90°; monoclinic (monohydrate, szomolnokite); a=7.62 Å, b=7.47 Å, c=7.12 Åα=90°, β=115.85°, γ=90°; monoclinic (tetrahydrate, rozenite); a=5.979 Å, b=13.648 Å, c=7.977 Åα=90°, β=90.26°, γ=90°; monoclinic (heptahydrate, melanterite); a=14.077 Å, b=6.509 Å, c=11.054 Åα=90°, β=105.6°, γ=90°;
Shapes:	https://en.crystalls.info/w/uploads/media/b/bc/Rhombic_prism.json Rhombic prism https://en.crystalls.info/w/uploads/media/3/37/Octahedron.json Octahedron https://en.crystalls.info/w/uploads/media/f/fd/Beveled_truncated_rhombic_prism.json Beveled truncated rhombic prism https://en.crystalls.info/w/uploads/media/f/fa/Truncated_rhombic_pyramid.json Truncated rhombic pyramid Template:Rhombohedron;
Color:	lime green (heptahydrate); emerald green (tetrahydrate); white (anhydrous);
Decomposition point:	680 °C953.15 K <br />1,256 °F <br />1,715.67 °R <br /> (anhydrous);
Refractive index:	1.591 (anhydrous); 1.526 (tetrahydrate); 1.471 (heptahydrate);
Magnetic properties:	paramagnetic; χ=1.24 · 10-2cm³/mol;
Stability:	highly erodes (heptahydrate); stable (tetrahydrate); hygroscopic (anhydrous);
Hardness:	relatively strong; (2 on Moh's scale);
Toxicity:	moderately toxic; LD50=237mg/kg

Description

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

Minerals

Occurs in nature as melanterite, rozenite and szomolnokite minerals.

Where to buy

Can be bought in fertilizers store (as "iron vitriol").

Precursors

Reaction between iron(II) hydroxycarbonate, hydroxide or oxide and sulfuric acid

Chemical equation:

2H₂SO₄ + Fe₂CO₃(OH)₂ = 2FeSO₄ + 3H₂O + CO₂↑

H₂SO₄ + Fe(OH)₂ = FeSO₄ + 2H₂O

H₂SO₄ + FeO = FeSO₄ + H₂O

For preparation of 100.00g of iron(II) sulfate

heptahydrateheptahydrate
tetrahydrate
anhydrous

а 32.32g of hydroxide or 25.84g of oxide and 95.35g of 37%37% sulfuric acid is required.

Add acid to the flask, then add small parts of iron 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 iron and sulfuric acid

Chemical equation:

H₂SO₄ + Fe = FeSO₄ + H₂↑

For preparation of 100.00g of iron(II) sulfate

heptahydrateheptahydrate
tetrahydrate
anhydrous

а 20.09g of iron and 95.35g of 37%37% sulfuric acid is required.

Add diluted acid solution to the flask, then add iron pieces, shavings or powder and stir it until gas emission will stop.

Reaction between metal iron and copper(II) sulfate

Chemical equation:

CuSO₄ + Fe = FeSO₄ + Cu↓

For preparation of 100.00g of iron(II) sulfate

heptahydrateheptahydrate
tetrahydrate
anhydrous

а 20.09g of iron and 89.81g of copper(II) sulfate

pentahydratepentahydrate
anhydrous

is required.

Add copper(II) sulfate solution to the flask, then add iron 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

While solution tempetature is above 56.8°C, mostly tetrahydrate crystal forms. However, the increase in temperature also leads to a faster hydrolysis of the substance, with simultaneous oxidation to Iron(III) sulfate.

Influence of impurities

Nickel sulfate impurities lead to formation of polycrystals with a darker color.

Influence of pH level

Addition of sulfuric acid positively affects crystals transparency and oxidation stability. It is highly recommended to use. Neutral solutions oxidise in few days and grows discolored fragile plates instead.
Any acidic household product, even if weak, such as potassium bisulfate or citric acid, suffices to produce tabular green crystals of heptahydrate, except oxalic acid, which destroys the iron sulfate. Acetic acid is also not recommended, as it may be catalysing oxidation due to oxidation instability of ferrous acetate. Such crystals is comparable to metallic calcium in stability (tarnishing in weeks, sustained damage on further standing) and must be placed in tightly closed container, under oil ideally.
The addition of more than 55% by weight (dissolution of heptahydrate directly in the battery electrolyte with further evaporation of excess water) leads to the growth of tetrahydrate crystals, much more resistant to erosion. Such crystals is only grown in strongly dehydrating environments, so other strong acids cannot be used.

Notes

Crystalverse.com site provides a step-by-step guide about growing crystals of iron(II) sulfate.

Solubility

TableGraph

Temperature	g/`100,00` g water		g/`100,00` g glycerol	g/`100,00` g ethylene glycol
Temperature	(anhydrous)	(heptahydrate)	(heptahydrate)	(heptahydrate)
0°C273.15 K <br />32 °F <br />491.67 °R <br />	`15.607`
10°C283.15 K <br />50 °F <br />509.67 °R <br />	`20.482`
15°C288.15 K <br />59 °F <br />518.67 °R <br />			`25`
20°C293.15 K <br />68 °F <br />527.67 °R <br />	`26.263`	`28.8`		`6.4`
25°C298.15 K <br />77 °F <br />536.67 °R <br />	`29.534`
30°C303.15 K <br />86 °F <br />545.67 °R <br />	`32.979`
40°C313.15 K <br />104 °F <br />563.67 °R <br />	`40.449`	`40`
50°C323.15 K <br />122 °F <br />581.67 °R <br />	`48.81`	`48.6`
60°C333.15 K <br />140 °F <br />599.67 °R <br />	`55.039`	`60`
70°C343.15 K <br />158 °F <br />617.67 °R <br />	`50.602`	`73.3`
80°C353.15 K <br />176 °F <br />635.67 °R <br />	`43.678`
90°C363.15 K <br />194 °F <br />653.67 °R <br />	`37.174`	`79.9`
100°C373.15 K <br />212 °F <br />671.67 °R <br />	`31.579`

Insoluble in ethanol.

Gallery

HeptahydrateIron(II) sulfate, Rostislav Dolgikh, VKontakteRostislav DolgikhVKontakte
HeptahydrateCopper(II) sulfate, Artem Pavlukov, VKontakteArtem PavlukovVKontakte
HeptahydrateIron(II) sulfate, Maxim Martinov, VKontakteMaxim MartinovVKontakte
HeptahydrateIron(II) sulfate, Martinov Maxim, VKontakteMartinov MaximVKontakte
Heptahydrate, weathering after a few weeks at open airIron(II) sulfate, Maxim Martinov, VKontakteMaxim MartinovVKontakte
HeptahydrateIron(II) sulfate, Vasily Furt, VKontakteVasily FurtVKontakte
HeptahydrateIron(II) sulfate, Artem Pavlukov, VKontakteArtem PavlukovVKontakte
TetrahydrateIron(II) sulfate, Gleb Vertyankin, VKontakteGleb VertyankinVKontakte
TetrahydrateIron(II) sulfate, Andrey Zmitrovich, VKontakteAndrey ZmitrovichVKontakte
TetrahydrateIron(II) sulfate, Viktoriya Shipova, VKontakteViktoriya ShipovaVKontakte
TetrahydrateIron(II) sulfate, Viktoriya Shipova, VKontakteViktoriya ShipovaVKontakte
TetrahydrateIron(II) sulfate, Maxim Martinov, VKontakteMaxim MartinovVKontakte
TetrahydrateIron(II) sulfate, Martinov Maxim, VKontakteMartinov MaximVKontakte

Video

Sources

Iron compounds
Salts	Iron (Fe) • Iron(II) acetate (Fe(CH₃COO)₂) • Iron(II) chloride (FeCl₂) • Iron(III) chloride (FeCl₃) • Iron(II) citrate (FeHC₃H₅O(COO)₃) • Iron(II) formate (Fe(COOH)₂) • Iron(III) formate (Fe₂(COOH)₃) • Iron(II) nitrate (Fe(NO₃)₂) • Iron(II) phosphate (Fe₃(PO₄)₂) • Iron(II) sulfate (FeSO₄) • Iron(III) sulfate (Fe₂(SO₄)₃)
Double salts	Iron(III)-ammonium sulfate ((NH₄)Fe(SO₄)₂) • Iron(II)-ammonium sulfate ((NH₄)₂Fe(SO₄)₂) • Iron(II)-potassium sulfate (K₂Fe(SO₄)₂) • Iron(II)-magnesium sulfate ((Fe,Mg)SO₄) • Copper(II)-iron(II) sulfate ((Cu,Fe)SO₄)
Complexes	Hexacyanoferrates • Nitroprussides‎ • Pentachloroferrates • Trioxalatoferrates • Sodium ethylenediaminetetraacetate-ferrate(III) (Na[Fe((OOCCH₂)₂N(CH₂)₂N(CH₂COO)₂)])

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)

Iron(II) sulfate
Names:	ferrous sulfate iron vitriol green vitriol
Formula:	FeSO₄ (anhydrous) FeSO₄ · 4H₂O (tetrahydrate) FeSO₄ · 7H₂O (heptahydrate)
Molar mass:	151.906 g/mol (anhydrous) 223.966 g/mol (tetrahydrate) 278.010 g/mol (heptahydrate)
Density:	3.56 g/cm³ (anhydrous) 3 g/cm³ (monohydrate) 2.15 g/cm³ (tetrahydrate) 1.898 g/cm³ (heptahydrate)
Crystal system:	orthorhombic (anhydrous) a=8.7042 Å, b=6.8013 Å, c=4.7868 Åα=90°, β=90°, γ=90° monoclinic (monohydrate, szomolnokite) a=7.62 Å, b=7.47 Å, c=7.12 Åα=90°, β=115.85°, γ=90° monoclinic (tetrahydrate, rozenite) a=5.979 Å, b=13.648 Å, c=7.977 Åα=90°, β=90.26°, γ=90° monoclinic (heptahydrate, melanterite) a=14.077 Å, b=6.509 Å, c=11.054 Åα=90°, β=105.6°, γ=90°
Shapes:	Rhombic prism Octahedron Beveled truncated rhombic prism Truncated rhombic pyramid Template:Rhombohedron
Color:	lime green (heptahydrate) emerald green (tetrahydrate) white (anhydrous)
Decomposition point:	680 °C953.15 K <br />1,256 °F <br />1,715.67 °R <br /> (anhydrous)
Refractive index:	1.591 (anhydrous) 1.526 (tetrahydrate) 1.471 (heptahydrate)
Magnetic properties:	paramagnetic χ=1.24 · 10^-2cm³/mol
Stability:	highly erodes (heptahydrate) stable (tetrahydrate) hygroscopic (anhydrous)
Hardness:	relatively strong (2 on Moh's scale)
Toxicity:	moderately toxic LD₅₀=237mg/kg

Description

Minerals

Where to buy

Precursors

Reaction between iron(II) hydroxycarbonate, hydroxide or oxide and sulfuric acid

Reaction between metal iron and sulfuric acid

Reaction between metal iron and copper(II) sulfate

Influence of temperature

Influence of impurities

Influence of pH level

Notes

Solubility

Gallery

Video

Sources

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