Editing Iron(II) sulfate (section)

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[[File:Ferric sulphate, Kemira.jpg|thumb|left|Iron(II) sulfate outside a [[titanium dioxide]] factory in Kaanaa, [[Pori]], Finland.]]
Upon dissolving in water, ferrous sulfates form the [[metal aquo complex]] [Fe(H<sub>2</sub>O)<sub>6</sub>]<sup>2+</sup>, which is an almost colorless, [[paramagnetic]] ion.

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 [[Chemical decomposition|decomposes]] into [[sulfur dioxide]] and [[sulfur trioxide]], leaving a reddish-brown [[iron(III) oxide]]. [[Thermal decomposition|Thermolysis]] of iron(II) sulfate begins at about {{convert|680|C|F}}.
:{{chem2 | 2 FeSO4 }} {{overset|&Delta;|&rarr;}} {{chem2 | Fe2O3 + SO2 + SO3 }}

Like other iron(II) salts, iron(II) sulfate is a reducing agent. For example, it reduces [[nitric acid]] to [[nitrogen monoxide]] and [[chlorine]] to [[chloride]]:
:{{chem2 | 6 FeSO4 + 3 H2SO4 + 2 HNO3 -> 3 Fe2(SO4)3 + 4 H2O + 2 NO }}
:{{chem2 | 6 FeSO4 + 3 Cl2 -> 2 Fe2(SO4)3 + 2 FeCl3 }}
Its mild reducing power is of value in organic synthesis.<ref>{{cite journal|journal=Org. Synth.|year=1948|volume=28|page=11|doi=10.15227/orgsyn.028.0011|title=o-Aminobenzaldehyde|author1=Lee Irvin Smith|author2=J. W. Opie}}</ref> It is used as the iron catalyst component of [[Fenton's reagent]].

Ferrous sulfate can be detected by the [[Cerimetry|cerimetric]] method, which is the official method of the [[Indian Pharmacopoeia Commission|Indian Pharmacopoeia.]] This method includes the use of ferroin solution showing a red to light green colour change during titration.<ref>{{Cite web |url=https://cpha.tu.edu.iq/images/%D8%B9%D9%85%D8%B1_%D8%AD%D8%B3%D9%8A%D9%86/ASSAY_OF_FERROUS_SULPHATE__ali_hussein-%D9%85%D8%AD%D9%88%D9%84_1.pdf |archive-url=https://web.archive.org/web/20230929051907/https://cpha.tu.edu.iq/images/%D8%B9%D9%85%D8%B1_%D8%AD%D8%B3%D9%8A%D9%86/ASSAY_OF_FERROUS_SULPHATE__ali_hussein-%D9%85%D8%AD%D9%88%D9%84_1.pdf |archive-date=2023-09-29 |last=Al-Obaidi |first=Ali Hussein Mustafa|title=ASSAY OF FERROUS SULPHATE }}</ref>