Names | |
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IUPAC name
Iron(II) oxalate
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Other names
Iron oxalate
Ferrous oxalate | |
Identifiers | |
3D model (
JSmol)
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ECHA InfoCard | 100.007.472 |
EC Number |
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PubChem
CID
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UNII |
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CompTox Dashboard (
EPA)
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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 | dihydrate: 150–160 °C (302–320 °F; 423–433 K) (decomposes) |
dihydrate: 0.097 g/100ml (25 °C) [1] | |
Hazards | |
GHS labelling: | |
[2] | |
Warning | |
H302, H312 [2] | |
P280 [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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Ferrous oxalate (iron(II) oxalate) are inorganic compound with the formula FeC2O4(H2O)x where x is 0 or 2. These are orange compounds, poorly soluble in water.
Like other iron oxalates, ferrous oxalates feature octahedral Fe centers. The dihydrate FeC2O4(H2O)x is a
coordination polymer, consisting of chains of oxalate-bridged ferrous centers, each with two aquo ligands.
[3]
When heated to 120 °C, the dihydrate dehydrates, and the anhydrous ferrous oxalate decomposes near 190 °C. [4] The products of thermal decomposition is a mixture of iron oxides and pyrophoric iron metal, as well as released carbon dioxide, carbon monoxide, and water. [5]
Ferrous oxalates are precursors to iron phosphates, which are of value in batteries. [6]
Anhydrous iron(II) oxalate is unknown among minerals as of 2020. However, the dihydrate is known as
humboldtine.
[7]
[8] A related, though much more complex mineral is
stepanovite,
Na[Mg(H2O)6] [Fe3+(C2O4)3]·3H2O - an example of trioxalatoferrate(III).
[9]
[8]