Iron(II) oxalate


Ferrous oxalate (iron(II) oxalate) is an inorganic compound with the formula FeC2O4 · x H2O where x is typically 2. These are orange compounds, poorly soluble in water.

Iron(II) oxalate
IUPAC name
Iron(II) oxalate
Other names
Iron oxalate
Ferrous oxalate
  • 516-03-0 checkY
  • 6047-25-2 (dihydrate) checkY
3D model (JSmol)
  • Interactive image
ECHA InfoCard 100.007.472 Edit this at Wikidata
EC Number
  • 208-217-4
  • 10589
  • DZP4YV3ICV checkY
  • Z6X3YBU50D (dihydrate) checkY
  • DTXSID4060159 Edit this at Wikidata
  • InChI=1S/3C2H2O4.2Fe/c3*3-1(4)2(5)6;;/h3*(H,3,4)(H,5,6);;/q;;;2*+3/p-6 ☒N
  • [Fe+2].O=C([O-])-C([O-])=O
FeC2O4 (anhydrous)
FeC2O4 · 2 H2O (dihydrate)
Molar mass 143.86 g/mol (anhydrous)
179.89 g/mol (dihydrate)
Appearance yellow powder
Odor odorless
Density 2.28 g/cm3
Melting point dihydrate: 150–160 °C (302–320 °F; 423–433 K)
0.097 g/100ml (25 °C)[1]
GHS labelling:
GHS07: Exclamation mark[2]
H302, H312[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Structure Edit

The dihydrate FeC2O4 · 2 H2O is a coordination polymer, consisting of chains of oxalate-bridged ferrous centers, each with two aquo ligands.[3]

When heated, it dehydrates and decomposes into a mixture of iron oxides and pyrophoric iron metal, with release of carbon dioxide, carbon monoxide, and water.[4]

Natural occurrence Edit

Anhydrous iron(II) oxalate is as yet (2020) unknown among minerals. However, the dihydrate is known, as humboldtine.[5][6] A related, though much more complex mineral is stepanovite,
Na[Mg(H2O)6] [Fe3+(C2O4)3]·3H2O - an example of trioxalatoferrate(III).[7][6]

See also Edit

References Edit

  1. ^ "Iron(II) oxalate dihydrate".
  2. ^ a b c Sigma-Aldrich Co., Iron(II) oxalate dihydrate. Retrieved on 2014-05-03.
  3. ^ Echigo, Takuya; Kimata, Mitsuyoshi (2008). "Single-crystal X-ray diffraction and spectroscopic studies on humboldtine and lindbergite: weak Jahn–Teller effect of Fe2+ ion". Physics and Chemistry of Minerals. 35 (8): 467–475. Bibcode:2008PCM....35..467E. doi:10.1007/s00269-008-0241-7. S2CID 98739882.
  4. ^ Hermanek, Martin; Zboril, Radek; Mashlan, Miroslav; Machala, Libor; Schneeweiss, Oldrich (2006). "Thermal behaviour of iron(II) oxalate dihydrate in the atmosphere of its conversion gases". J. Mater. Chem. 16 (13): 1273–1280. doi:10.1039/b514565a.
  5. ^ "Humboldtine".
  6. ^ a b "List of Minerals". 21 March 2011.
  7. ^ "Stepanovite".