Iron(II) selenate
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| Name = Iron(II) selenate
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| OtherNames = Ferrous selenate
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| Section1 = {{Chembox Identifiers
| index_label=(anhydrous)
| index1_label=(pentahydrate)
| CASNo_Ref = CAS No. from SciFinder
| CASNo = 15857-43-9
| CASNo1 = 70807-08-8
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| PubChem = 159739849
| SMILES = [O-][Se](=O)(=O)[O-].[Fe+2]
| SMILES1 = [O-][Se](=O)(=O)[O-].[Fe+2].O.O.O.O.O
| InChI=1S/Fe.H2O4Se/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2
| InChIKey=NCHUFZYUFAWBQI-UHFFFAOYSA-L
| InChI1=1S/Fe.H2O4Se.5H2O/c;1-5(2,3)4;;;;;/h;(H2,1,2,3,4);5*1H2/q+2;;;;;;/p-2
| InChIKey1=YXLBLVIIVLRXHU-UHFFFAOYSA-L
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| Section3 = {{Chembox Properties
| Formula = FeSeO4
| MolarMass = 198.8046 g/mol (anhydrous)
288.881 g/mol (pentahydrate)
324.91156 g/mol (heptahydrate)
| Appearance = green, unstable crystalline solid (heptahydrate)
| Solubility = soluble
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Iron(II) selenate (ferrous selenate) is an inorganic compound with the formula FeSeO4. It has anhydrous and several hydrate forms. The pentahydrate has the structure, [Fe(H2O)4]SeO4•H2O, isomorphous to the corresponding iron(II) sulfate.K. Heinzinger, G. Pálinkás, Hubertus Kleeberg. Interactions of Water in Ionic and Nonionic Hydrates: Proceedings of a Symposium in honour of the 65th birthday of W.A.P. Luck Marburg/FRG, 2.–3.4. 1987. Springer-Verlag Berlin Heidelberg, 1987 Heptahydrate is also known, in form of unstable green crystalline solid.
Preparation
Iron(II) selenate can be prepared by the reaction of saturated sodium selenate and iron(II) sulfate at 80 °C. When cooled to room temperature, crystalline iron(II) selenate precipitates from the solution.Filonenko, E. N.; Vergeichik, E. N.. Preparation and analysis of cobalt (II) selenate and iron (II) selenate. Farmatsiya (Moscow), 1998. 47 (3): 36-37
: Na2SeO4 (sat.) + FeSO4 → Na2SO4 + FeSeO4
The reaction of iron and selenic acid produces iron(II) selenate as well, but with a side product:A E H Tutton. [http://rspa.royalsocietypublishing.org/content/royprsa/94/661/352.full.pdf Selenic Acid and Iron. - Reduction of Selenic Acid by Nascent Hydrogen and Hydrogen Sulphide. - Preparation of Ferrous Selenate and Double Selenates of Iron Group]. Proceedings of the Royal Society A, 1918 , 94 (241) :352-361
: Fe + H2SeO4 → FeSeO4 + H2↑
: 3 Fe + 4 H2SeO4 → 3 FeSeO4 + Se + 4 H2O
Other species containing oxoanion of selenium
Double salts like the Tutton's salts (NH4)2Fe(SeO4)2•6H2O and K2Fe(SeO4)2•6H2O are known.
In addition to the ferrous (Fe2+) salt, the ferric (Fe3+) salt iron(III) selenate, Fe2(SeO4)3, has also been reported.G Giester, F Pertlik. Synthesis and crystal structure of iron(III) selenate(IV) trihydrate, Fe2(SeO3)3·3H2O. Journal of Alloys & Compounds, 1994 , 210 (1-2) :125-128
However, iron(II) selenite (FeSeO3) is unknown, though the selenite and pyroselenite of iron(III) was published.Pinaev, G. F.; Stukan, R. A.; Makarov, E. F.. Moessbauer effect in iron(3+) selenites. Zhurnal Neorganicheskoi Khimii, 1977. 22 (7): 1731-1733