Iron(II) sulfate
Iron(II) sulfate when dissolved in water
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Names | |
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IUPAC name
Iron(II) sulfate
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Other names
Iron(II) sulphate; Ferrous sulfate, Green vitriol, Iron vitriol, Ferrous vitriol, Copperas, Melanterite, Szomolnokite,
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Identifiers | |
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3D model (
JSmol ) |
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ChEBI |
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ChEMBL |
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ChemSpider | |
ECHA InfoCard
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100.028.867 |
EC Number |
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PubChem CID
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RTECS number
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UNII |
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UN number | 3077 |
CompTox Dashboard (EPA)
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Properties | |
FeSO4 | |
Molar mass | 151.91 g/mol (anhydrous) 169.93 g/mol (monohydrate) 241.99 g/mol (pentahydrate) 260.00 g/mol (hexahydrate) 278.02 g/mol (heptahydrate) |
Appearance | White crystals (anhydrous) White-yellow crystals (monohydrate) Blue-green deliquescent[1] crystals (heptahydrate)
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Odor | Odorless |
Density | 3.65 g/cm3 (anhydrous) 3 g/cm3 (monohydrate) 2.15 g/cm3 (pentahydrate)[2] 1.934 g/cm3 (hexahydrate)[3] 1.895 g/cm3 (heptahydrate)[4] |
Melting point | 680 °C (1,256 °F; 953 K) (anhydrous) decomposes[6] 300 °C (572 °F; 573 K) (monohydrate) decomposes 60–64 °C (140–147 °F; 333–337 K) (heptahydrate) decomposes[4][11] |
Monohydrate: 44.69 g/100 mL (77 °C) 35.97 g/100 mL (90.1 °C) Heptahydrate: 15.65 g/100 mL (0 °C) 19.986 g/100 mL (10 °C) 29.51 g/100 mL (25 °C) 39.89 g/100 mL (40.1 °C) 51.35 g/100 mL (54 °C)[5] | |
Solubility | Negligible in alcohol |
Solubility in ethylene glycol | 6.38 g/100 g (20 °C)[6] |
Vapor pressure | 1.95 kPa (heptahydrate)[7] |
1.24×10−2 cm3/mol (anhydrous) 1.05×10−2 cm3/mol (monohydrate) 1.12×10−2 cm3/mol (heptahydrate)[4] +10200×10−6 cm3/mol | |
Refractive index (nD)
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1.591 (monohydrate)[8] 1.526–1.528 (21 °C, tetrahydrate)[9] 1.513–1.515 (pentahydrate)[2] 1.468 (hexahydrate)[3] 1.471 (heptahydrate)[10] |
Structure | |
Pnma, No. 62 (anhydrous) [12] C2/c, No. 15 (monohydrate, hexahydrate)[3][8] P21/n, No. 14 (tetrahydrate)[9] P1, No. 2 (pentahydrate)[2] P21/c, No. 14 (heptahydrate)[10] | |
2/m 2/m 2/m (anhydrous)[12] 2/m (monohydrate, tetrahydrate, hexahydrate, heptahydrate)[3][8][9][10] 1 (pentahydrate)[2] | |
a = 8.704(2) Å, b = 6.801(3) Å, c = 4.786(8) Å (293 K, anhydrous)[12] α = 90°, β = 90°, γ = 90°
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Octahedral (Fe2+) | |
Thermochemistry | |
Heat capacity (C)
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100.6 J/mol·K (anhydrous)[4] 394.5 J/mol·K (heptahydrate)[13] |
Std molar
entropy (S⦵298) |
107.5 J/mol·K (anhydrous)[4] 409.1 J/mol·K (heptahydrate)[13] |
Std enthalpy of (ΔfH⦵298)formation |
−928.4 kJ/mol (anhydrous)[4] −3016 kJ/mol (heptahydrate)[13] |
Gibbs free energy (ΔfG⦵)
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−820.8 kJ/mol (anhydrous)[4] −2512 kJ/mol (heptahydrate)[13] |
Pharmacology | |
B03AA07 (WHO) | |
none | |
Pharmacokinetics: | |
4 days [14] | |
Duration of action |
2-4 months with peak activity at 7-10 days [15] |
Legal status |
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Hazards | |
GHS labelling: | |
[7] | |
Warning | |
H302, H315, H319[7] | |
P305+P351+P338[7] | |
NFPA 704 (fire diamond) | |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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237 mg/kg (rat, oral)[11] |
NIOSH (US health exposure limits): | |
REL (Recommended)
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TWA 1 mg/m3[16] |
Related compounds | |
Other cations
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Cobalt(II) sulfate Copper(II) sulfate Manganese(II) sulfate Nickel(II) sulfate |
Related compounds
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Iron(III) sulfate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Iron(II) sulfate (
It is on the World Health Organization's List of Essential Medicines.[19] In 2021, it was the 105th most commonly prescribed medication in the United States, with more than 6 million prescriptions.[20][21]
Uses
Industrially, ferrous sulfate is mainly used as a precursor to other iron compounds. It is a
Medical use
Plant growth
Iron(II) sulfate is sold as ferrous sulfate, a soil amendment[23] for lowering the pH of a high alkaline soil so that plants can access the soil's nutrients.[24]
In horticulture it is used for treating iron chlorosis.[25] Although not as rapid-acting as ferric EDTA, its effects are longer-lasting. It can be mixed with compost and dug into the soil to create a store which can last for years.[26] Ferrous sulfate can be used as a lawn conditioner.[26] It can also be used to eliminate silvery thread moss in golf course putting greens.[27]
Pigment and craft
Ferrous sulfate can be used to stain concrete and some limestones and sandstones a yellowish rust color.[28]
Green vitriol is also a useful reagent in the identification of mushrooms.[29]
Historical uses
Ferrous sulfate was used in the manufacture of
Two different methods for the direct application of indigo dye were developed in England in the 18th century and remained in use well into the 19th century. One of these, known as china blue, involved iron(II) sulfate. After printing an insoluble form of indigo onto the fabric, the indigo was reduced to leuco-indigo in a sequence of baths of ferrous sulfate (with reoxidation to indigo in air between immersions). The china blue process could make sharp designs, but it could not produce the dark hues of other methods.
In the second half of the 1850s ferrous sulfate was used as a photographic developer for collodion process images.[32]
Hydrates
Iron(II) sulfate can be found in various states of hydration, and several of these forms exist in nature or were created synthetically.
- FeSO4·H2O (mineral: szomolnokite,[8] relatively rare, monoclinic[33])
- FeSO4·H2O (synthetic compound stable at pressures exceeding 6.2 GPa, triclinic[33])
- FeSO4·4H2O (mineral: rozenite,[9][34] white, relatively common, may be dehydration product of melanterite, monoclinic[35])
- FeSO4·5H2O (mineral: siderotil,[2][36] relatively rare, triclinic[37])
- FeSO4·6H2O (mineral: ferrohexahydrite,[3][38] very rare, monoclinic[37])
- FeSO4·7H2O (mineral: melanterite,[10][39] blue-green, relatively common, monoclinic[40])
The tetrahydrate is stabilized when the temperature of aqueous solutions reaches 56.6 °C (133.9 °F). At 64.8 °C (148.6 °F) these solutions form both the tetrahydrate and monohydrate.[5]
Mineral forms are found in oxidation zones of iron-bearing ore beds, e.g. pyrite, marcasite, chalcopyrite, etc. They are also found in related environments, like coal fire sites. Many rapidly dehydrate and sometimes oxidize. Numerous other, more complex (either basic, hydrated, and/or containing additional cations) Fe(II)-bearing sulfates exist in such environments, with copiapite being a common example.[41]
Production and reactions
In the finishing of steel prior to plating or coating, the steel sheet or rod is passed through pickling baths of sulfuric acid. This treatment produces large quantities of iron(II) sulfate as a by-product.[42]
- Fe + H2SO4 → FeSO4 + H2
Another source of large amounts results from the production of titanium dioxide from ilmenite via the sulfate process.
Ferrous sulfate is also prepared commercially by oxidation of pyrite:[43]
- 2 FeS2 + 7 O2 + 2 H2O → 2 FeSO4 + 2 H2SO4
It can be produced by displacement of metals less reactive than Iron from solutions of their sulfate:
- CuSO4 + Fe → FeSO4 + Cu
Reactions
Upon dissolving in water, ferrous sulfates form the
On heating, iron(II) sulfate first loses its water of crystallization and the original green crystals are converted into a white anhydrous solid. When further heated, the anhydrous material decomposes into sulfur dioxide and sulfur trioxide, leaving a reddish-brown iron(III) oxide. Thermolysis of iron(II) sulfate begins at about 680 °C (1,256 °F).
Like other iron(II) salts, iron(II) sulfate is a reducing agent. For example, it reduces
:- 6 FeSO4 + 3 H2SO4 + 2 HNO3 → 3 Fe2(SO4)3 + 4 H2O + 2 NO
- 6 FeSO4 + 3 Cl2 → 2 Fe2(SO4)3 + 2 FeCl3
Its mild reducing power is of value in organic synthesis.[44] It is used as the iron catalyst component of Fenton's reagent.
Ferrous sulfate can be detected by the cerimetric method, which is the official method of the Indian Pharmacopoeia. This method includes the use of ferroin solution showing a red to light green colour change during titration.[45]
See also
- Iron(III) sulfate (ferric sulfate), the other common simple sulfate of iron.
- Copper(II) sulfate
- Ammonium iron(II) sulfate, also known as Mohr's salt, the common double salt of ammonium sulfate with iron(II) sulfate.
- Chalcanthum
- Ephraim Seehl known as an early manufacturer of Iron(II) sulfate, which he called 'green vitriol'.[46]
References
- PMID 29608281.
- ^ a b c d e f "Siderotil Mineral Data". Retrieved 3 August 2014.
- ^ a b c d e f "Ferrohexahydrite Mineral Data". Retrieved 3 August 2014.
- ^ ISBN 978-1-4200-9084-0.
- ^ a b Seidell A, Linke WF (1919). Solubilities of Inorganic and Organic Compounds (2nd ed.). New York: D. Van Nostrand Company. p. 343.
- ^ a b Anatolievich KR. "iron(II) sulfate". Retrieved 3 August 2014.
- ^ a b c d Sigma-Aldrich Co., Iron(II) sulfate heptahydrate. Retrieved on 3 August 2014.
- ^ a b c d e Ralph J, Chautitle I. "Szomolnokite". Mindat.org. Retrieved 3 August 2014.
- ^ a b c d e "Rozenite Mineral Data". Retrieved 3 August 2014.
- ^ a b c d e "Melanterite Mineral Data". Retrieved 3 August 2014.
- ^ a b "MSDS of Ferrous sulfate heptahydrate". Fair Lawn, New Jersey: Fisher Scientific, Inc. Retrieved 3 August 2014.
- ^ . Retrieved 3 August 2014.
- ^ a b c d Anatolievich KR. "iron(II) sulfate heptahydrate". Retrieved 3 August 2014.
- ^ "Ferrous sulfate". go.drugbank.com. Retrieved 11 December 2023.
- ^ "Ferrous sulfate". go.drugbank.com. Retrieved 11 December 2023.
- ^ NIOSH Pocket Guide to Chemical Hazards. "#0346". National Institute for Occupational Safety and Health (NIOSH).
- ^ Safety Data Sheet
- ISBN 0-19-861271-0.
- hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
- ^ "The Top 300 of 2021". ClinCalc. Archived from the original on 15 January 2024. Retrieved 14 January 2024.
- ^ "Ferrous Sulfate - Drug Usage Statistics". ClinCalc. Retrieved 14 January 2024.
- ^ British Archaeology magazine. http://www.archaeologyuk.org/ba/ba66/feat2.shtml (archive)
- ^ "Why Use Ferrous Sulfate for Lawns?". Retrieved 14 April 2018.
- ^ "Acid or alkaline soil: Modifying pH - Sunset Magazine". www.sunset.com. 3 September 2004. Retrieved 14 April 2018.
- ^ Koenig, Rich and Kuhns, Mike: Control of Iron Chlorosis in Ornamental and Crop Plants. (Utah State University, Salt Lake City, August 1996) p.3
- ^ ISBN 0-643-06677-2.
- ^ Controlling moss in putting greens by Cook, Tom; McDonald, Brian; and Merrifield, Kathy.
- ^ How To Stain Concrete with Iron Sulfate
- ISBN 0-7064-0448-3.
- ^ Torczyner, Lachish Letters, pp. 188–95
- ^ Hyatt, The Interpreter's Bible, 1951, volume V, p. 1067
- OCLC 558063884.
- ^ S2CID 197070809.
- ^ "Rozenite".
- ^ Meusburger J (September 2022). "Low-temperature crystallography and vibrational properties of rozenite (FeSO4·4H2O), a candidate mineral component of the polyhydrated sulfate deposits on Mars" (PDF).
- ^ "Siderotil".
- ^ a b "Metal-sulfate Salts from Sulfide Mineral Oxidation". pubs.geoscienceworld.org. Retrieved 18 November 2022.
- ^ "Ferrohexahydrite".
- ^ "Melanterite".
- ^ Peterson RC (2003). "THE RELATIONSHIP BETWEEN Cu CONTENT AND DISTORTION IN THE ATOMIC STRUCTURE OF MELANTERITE FROM THE RICHMOND MINE, IRON MOUNTAIN, CALIFORNIA" (PDF).
- ^ "Copiapite".
- ISBN 978-3527306732.
- .
- .
- ^ Al-Obaidi AH. "ASSAY OF FERROUS SULPHATE" (PDF). Archived from the original (PDF) on 29 September 2023.
- ^ Pryce W (1778). Mineralogia Cornubiensis; a Treatise on Minerals, Mines and Mining. London: Phillips. p. 33.
External links
- "Product Information". Chemical Land21. 10 January 2007.
- The American Cyclopædia.