Editing Iron(II) sulfate (section)

==Hydrates==
Iron(II) sulfate can be found in various states of [[hydrate|hydration]], and several of these forms exist in nature or were created synthetically.
* FeSO<sub>4</sub>·H<sub>2</sub>O (mineral: [[szomolnokite]],<ref name=mindat>{{cite web|first1= Jolyon|last1= Ralph|first2= Ida|last2= Chautitle|title= Szomolnokite|url= http://www.mindat.org/min-3859.html|publisher= [[Mindat.org]]|access-date= 3 August 2014}}</ref> relatively rare, [[Monoclinic crystal system|monoclinic]]<ref name=":0">{{Cite journal |last=Meusburger |first=Johannes |date=September 2019 |title=Transformation mechanism of the pressure-induced C2/c-to-P transition in ferrous sulfate monohydrate single crystals |journal=Journal of Solid State Chemistry |volume=277 |pages=240–252 |doi=10.1016/j.jssc.2019.06.004 |s2cid=197070809 |url=https://www.sciencedirect.com/science/article/abs/pii/S0022459619302853}}</ref>)
* FeSO<sub>4</sub>·H<sub>2</sub>O (synthetic compound stable at pressures exceeding 6.2 GPa, [[Triclinic crystal system|triclinic]]<ref name=":0" />)
* FeSO<sub>4</sub>·4H<sub>2</sub>O (mineral: [[rozenite]],<ref name="webmin">{{cite web|title= Rozenite Mineral Data|url= http://www.webmineral.com/data/Rozenite.shtml|access-date= 3 August 2014}}</ref><ref>{{Cite web|url=https://www.mindat.org/min-3469.html|title=Rozenite}}</ref> white, relatively common, may be dehydration product of melanterite, monoclinic<ref>{{Cite web |last=Meusburger |first=Johannes |date=September 2022 |title=Low-temperature crystallography and vibrational properties of rozenite (FeSO4·4H2O), a candidate mineral component of the polyhydrated sulfate deposits on Mars |url=http://www.minsocam.org/msa/ammin/AM_Preprints/8502ForbesPreprint.pdf}}</ref>)
* FeSO<sub>4</sub>·5H<sub>2</sub>O (mineral: [[siderotil]],<ref name="webmin2">{{cite web|title= Siderotil Mineral Data|url= http://www.webmineral.com/data/Siderotil.shtml|access-date= 3 August 2014}}</ref><ref>{{Cite web|url=https://www.mindat.org/min-3643.html|title=Siderotil}}</ref> relatively rare, triclinic<ref name=":1">{{Cite journal |url=https://pubs.geoscienceworld.org/msa/rimg/article-abstract/40/1/303/140666/Metal-sulfate-Salts-from-Sulfide-Mineral-Oxidation?redirectedFrom=fulltext |access-date=18 November 2022|title= Metal-sulfate Salts from Sulfide Mineral Oxidation|journal=Reviews in Mineralogy and Geochemistry|date=2000 |doi=10.2138/rmg.2000.40.6 |volume=40 |issue=1 |pages=303–350 |bibcode=2000RvMG...40..303J | vauthors = Jambor JL, Nordstrom DK, Alpers CN }}</ref>)
* FeSO<sub>4</sub>·6H<sub>2</sub>O (mineral: [[ferrohexahydrite]],<ref name="webmin3">{{cite web|title= Ferrohexahydrite Mineral Data|url= http://www.webmineral.com/data/Ferrohexahydrite.shtml|access-date= 3 August 2014}}</ref><ref>{{Cite web|url=https://www.mindat.org/min-1517.html|title=Ferrohexahydrite}}</ref> very rare, monoclinic<ref name=":1" />)
* FeSO<sub>4</sub>·7H<sub>2</sub>O (mineral: [[melanterite]],<ref name="webmin4">{{cite web|title= Melanterite Mineral Data|url= http://www.webmineral.com/data/Melanterite.shtml|access-date= 3 August 2014}}</ref><ref>{{Cite web|url=https://www.mindat.org/min-2633.html|title=Melanterite}}</ref> blue-green, relatively common, monoclinic<ref>{{Cite web |last=Peterson |first=RC |date=2003 |title=THE RELATIONSHIP BETWEEN Cu CONTENT AND DISTORTION IN THE ATOMIC STRUCTURE OF MELANTERITE FROM THE RICHMOND MINE, IRON MOUNTAIN, CALIFORNIA |url=https://rruff.info/doclib/cm/vol41/CM41_937.pdf}}</ref>)

[[File:Síran železnatý.PNG|thumb|left|Anhydrous iron(II) sulfate]]
The tetrahydrate is stabilized when the temperature of aqueous solutions reaches {{convert|56.6|C|F}}. At {{convert|64.8|C|F}} these solutions form both the tetrahydrate and monohydrate.<ref name=sioc>{{cite book|last1= Seidell|first1= Atherton|last2= Linke|first2= William F.|year= 1919|title= Solubilities of Inorganic and Organic Compounds|url= https://archive.org/details/solubilitiesino01seidgoog|publisher= D. Van Nostrand Company|place= [[New York City|New York]]|edition= 2nd|page= [https://archive.org/details/solubilitiesino01seidgoog/page/n368 343]}}</ref>

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.<ref name=Mindat>{{Cite web|url=https://www.mindat.org/min-1124.html|title=Copiapite}}</ref>