Iron(II) oxalate
Ferrous oxalate, or 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.
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| Names | |
|---|---|
| IUPAC name Iron(II) oxalate | |
| Other names Iron oxalate Ferrous oxalate | |
| Identifiers | |
| 3D model (JSmol) | |
| ECHA InfoCard | 100.007.472 | 
| EC Number | 
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| PubChem CID | |
| UNII | 
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| CompTox Dashboard (EPA) | |
| 
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| 
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| Properties | |
| 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 | 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] | 
| dihydrate: 0.097 g/100ml (25 °C)[2] | |
| Hazards | |
| GHS labelling: | |
|  [3] | |
| Warning | |
| H302, H312[3] | |
| P280[3] | |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references | |
Structure
    
The dihydrate FeC2O4 · 2 H2O is a coordination polymer, consisting of chains of oxalate-bridged ferrous centers, each with two aquo ligands.[4]
(H2O)2-chain-from-xtal-2008-CM-3D-balls.png.webp)
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.[5]
Natural occurrence
    
Anhydrous iron(II) oxalate is as yet (2020) unknown among minerals. However, the dihydrate is known, as humboldtine.[6][7] A related, though much more complex mineral is stepanovite, Na[Mg(H2O)6][Fe(C2O4)3]·3H2O - an example of trioxalatoferrate(II).[8][7]
See also
    
A number of other iron oxalates are known
References
    
- "CAS 516-03-0 products price,suppliers".
- "Iron(II) oxalate dihydrate".
- Sigma-Aldrich Co., Iron(II) oxalate dihydrate. Retrieved on 2014-05-03.
- 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 (8): 467–475. Bibcode:2008PCM....35..467E. doi:10.1007/s00269-008-0241-7. S2CID 98739882.
- 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 (13): 1273–1280. doi:10.1039/b514565a.
- "Humboldtine".
- "List of Minerals". 21 March 2011.
- "Stepanovite".

