Iron(II) selenate


Iron(II) selenate
Other names
Ferrous selenate
  • (anhydrous): 15857-43-9[1]
  • (pentahydrate): 70807-08-8
3D model (JSmol)
  • (anhydrous): Interactive image
  • (pentahydrate): Interactive image
  • (anhydrous): InChI=1S/Fe.H2O4Se/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2
  • (pentahydrate): InChI=1S/Fe.H2O4Se.5H2O/c;1-5(2,3)4;;;;;/h;(H2,1,2,3,4);5*1H2/q+2;;;;;;/p-2
  • (anhydrous): [O-][Se](=O)(=O)[O-].[Fe+2]
  • (pentahydrate): [O-][Se](=O)(=O)[O-].[Fe+2].O.O.O.O.O
Molar mass 198.8046 g/mol (anhydrous)
288.881 g/mol (pentahydrate)
324.91156 g/mol (heptahydrate)
Appearance green, unstable crystalline solid (heptahydrate)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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.[2] Heptahydrate is also known, in form of unstable green crystalline solid.[3]


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.[4]

Na2SeO4 (sat.) + FeSO4 → Na2SO4 + FeSeO4

The reaction of iron and selenic acid produces iron(II) selenate as well, but with a side product:[3]

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.[3]

In addition to the ferrous (Fe2+) salt, the ferric (Fe3+) salt iron(III) selenate, Fe2(SeO4)3, has also been reported.[5]

However, iron(II) selenite (FeSeO3) is unknown, though the selenite and pyroselenite of iron(III) was published.[6]


  1. ^ CAS No. from SciFinder
  2. ^ 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
  3. ^ a b c A E H Tutton. 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
  4. ^ Filonenko, E. N.; Vergeichik, E. N.. Preparation and analysis of cobalt (II) selenate and iron (II) selenate. Farmatsiya (Moscow), 1998. 47 (3): 36-37
  5. ^ 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
  6. ^ Pinaev, G. F.; Stukan, R. A.; Makarov, E. F.. Moessbauer effect in iron(3+) selenites. Zhurnal Neorganicheskoi Khimii, 1977. 22 (7): 1731-1733