Iron(II) oxalate

Iron(II) oxalate

Names
IUPAC name Iron(II) oxalate
Other names Iron oxalate Ferrous oxalate
Identifiers
CAS Number	516-03-0 6047-25-2 (dihydrate)
EC Number	208-217-4
Jmol interactive 3D	Image
PubChem	10589
InChI InChI=1S/3C2H2O4.2Fe/c3*3-1(4)2(5)6;;/h3*(H,3,4)(H,5,6);;/q;;;2*+3/p-6 Key: VEPSWGHMGZQCIN-UHFFFAOYSA-H
SMILES [Fe+3].[Fe+3].O=C([O-])C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O
Properties
Chemical formula	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/cm^3
Melting point	190 °C (374 °F; 463 K) (anhydrous)[1] 150–160 °C (302–320 °F; 423–433 K) (dihydrate) decomposes
Boiling point	365.1 °C (689.2 °F; 638.2 K) (anhydrous)[1]
Solubility in water	dihydrate: 0.097 g/100ml (25 °C)[2]
Hazards
GHS pictograms	[3]
GHS signal word	Warning
GHS hazard statements	H302, H312[3]
GHS precautionary statements	P280[3]
EU classification (DSD)	Xn
R-phrases	R21/22
S-phrases	S24/25
Flash point	188.8 °C (371.8 °F; 461.9 K)
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

Ferrous oxalate, or iron(II) oxalate, is a chemical compound consisting of one iron(II) ion (Fe²⁺) and one oxalate ion (C₂O₄²⁻). It has the chemical formula FeC₂O₄.

Iron(II) oxalate is more commonly encountered as the dihydrate, FeC₂O₄·2H₂O, CAS # 6047-25-2. Its crystal structure consists of chains of oxalate-bridged iron atoms, capped by water molecules.^[4]

When heated, it dehydrates and decomposes into carbon dioxide, carbon monoxide, iron oxides and pyrophoric black iron. ^[5]

Safety

Iron(II) oxalate is harmful when swallowed. It may cause irritation to eyes and skin.

See also

A number of other iron oxalates are known

• Iron(III) oxalate
• Potassium ferrioxalate
• Sodium ferrioxalate

References

1. http://www.guidechem.com/cas-516/516-03-0.html
2. http://chemister.ru/Database/properties-en.php?dbid=1&id=2084
3. Sigma-Aldrich Co., Iron(II) oxalate dihydrate. Retrieved on 2014-05-03.
4. Echigo, Takuya; Kimata, Mitsuyoshi (2008). "Single-crystal X-ray diffraction and spectroscopic studies on humboldtine and lindbergite: weak Jahn–Teller effect of Fe²⁺ ion". Phys. Chem. Minerals 35: 467–475. doi:10.1007/s00269-008-0241-7.
5. Hermanek, Martin; Zboril, Radek; Mashlan, Miroslav; et al. (2006). "Thermal behaviour of iron(II) oxalate dihydrate in the atmosphere of its conversion gases". J. Mater. Chem. 16: 1273–1280.