 | |
| Names | |
|---|---|
| IUPAC name Sodium iron(III) oxalate, sodium oxalatoferrate, sodium trisoxalatoferrate | |
| Other names Sodium ferrioxalate Sodium ferric oxalate | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.008.267 |
| EC Number |
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| |
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| Properties | |
| C6FeNa3O12 | |
| Molar mass | 388.868 g·mol−1 |
| Appearance | lime green hydrated crystals |
| Density | 1.97 g/cm3 at 17 °C |
| 32.5pts per 100pts solvent, cold water, 182pts per 100pts, boiling water[1] | |
| Structure | |
| octahedral | |
| 0D | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | Corrosive. Eye, respiratory and skin irritant. |
| GHS labelling: | |
 | |
| Warning | |
| H302,H312 | |
| P264,P270,P280,P301+P312,P302+P352,P312,P322,P330,P363,P501 | |
| Related compounds | |
Otheranions | Potassium ferrioxalate |
Related compounds | Iron(II) oxalate Iron(III) oxalate |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Sodium ferrioxalate areinorganic compounds with the formulaNa3Fe(C2O4)3(H2O)n. The pentahydrate has been characterized byX-ray crystallography. In contrast the potassium, ammonium, and rubidium salts crystallize from water as their trihydrates.[2]
The compound is asalt consisting offerrioxalateanions,[Fe(C2O4)3]3−, andsodium cationsNa+. The anion is atransition metal complex consisting of aniron atom in the +3 oxidation state and threebidentateoxalate ionsC2O2−4 anions serving asligands.
The ferrioxalate anion is sensitive to light and higher-energyelectromagnetic radiation, which causes the decomposition of one oxalate tocarbon dioxideCO2 and reduction of the iron(III) atom toiron(II).
Sodium ferrioxalate can be obtained by mixing solutions ofsodium oxalate andferric oxalate, and waiting a few hours for the brown colour of the ferric oxalate to be replaced with the green colour of the complex anion.
The equilibrium is attained only slowly at room temperature. The product can then be crystallized by evaporating the solution at just below boiling until small crystals appear, then allowing it to cool. The product may also be precipitated by addingmethanol orethanol to the solution.
Some decomposition of the ferric oxalate may occur during the process, resulting in the canary-yellow insolubleiron(II) oxalate. Small amounts ofhydrogen peroxideH2O2 may be added to keep the iron in the 3+ oxidation state.
A number of other iron oxalates are known
