Ferrous oxalate dihydrate
[CAS# 6047-25-2]

Identification

• Classification: Organic raw materials >> Organometallic salt
• Name: Ferrous oxalate dihydrate
• Synonyms: Iron(II) oxalate dihydrate
• Molecular Formula: Fe.(C₂O₄).2(H₂O)
• Molecular Weight: 179.89
• CAS Registry Number: 6047-25-2
• EC Number: 611-981-5
• SMILES: C(=O)(C(=O)[O-])[O-].O.O.[Fe+2]

Properties

• Solubility: Soluble (acids)
• Density: 2.28 g/mL
• Melting point: 2200 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H312
• Safety Statements: P264-P270-P280-P301+P317-P302+P352-P317-P321-P330-P362+P364-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H312

Discovery and Applications

Ferrous oxalate dihydrate, also known as iron(II) oxalate dihydrate, is an inorganic compound with the formula FeC₂O₄·2H₂O. It consists of iron in the +2 oxidation state, coordinated with oxalate ions and two molecules of water. The compound appears as a pale yellow solid and is commonly used in both chemical and industrial processes.

The discovery of ferrous oxalate dihydrate dates back to the 19th century when chemists first explored the coordination chemistry of iron. Oxalate compounds were studied due to their ability to form stable complexes with various metal ions, including iron. Ferrous oxalate dihydrate is typically prepared by reacting an aqueous solution of ferrous sulfate with oxalic acid, resulting in the precipitation of the oxalate salt. The compound’s crystalline form contains two molecules of water, which contribute to its stability under ambient conditions.

Ferrous oxalate dihydrate finds several applications, particularly in the field of material science. One of its primary uses is as a precursor in the thermal decomposition process to produce iron oxides. When heated, ferrous oxalate dihydrate decomposes to form iron(II) oxide (FeO) or iron(III) oxide (Fe₂O₃), depending on the specific conditions. These iron oxides are essential in various industries, especially in the production of pigments, magnetic materials, and catalysts.

Another important application of ferrous oxalate dihydrate is in the field of photography, where it has been used historically in the preparation of light-sensitive iron salts for photographic printing processes. In particular, it plays a role in alternative photographic techniques such as cyanotype and platinotype, which rely on the reduction of iron salts to create images.

Ferrous oxalate dihydrate is also relevant in research, where it is used in the study of metal-organic frameworks (MOFs) and coordination polymers. Its ability to form extended networks with other metal ions and organic ligands makes it a valuable building block for designing novel materials with specific properties, such as gas storage or catalysis.

References

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