Ammonium ferric citrate NEW

Ammonium ferric citrate is a chemical compound with a complex structure, essentially a complex salt of iron and ammonia with citric acid. It appears as thin, transparent, green or brownish-red scales or granules, or as a powder.

It has two common forms, which are often specified:

• Green Ammonium Ferric Citrate: More common and used in various applications.

  Brown Ammonium Ferric Citrate: Has a slightly different composition and is primarily used in a specific historical photographic process.

Its key feature is that it is soluble in water, making it a useful source of bioavailable iron.

Key Properties and Characteristics

• Chemical Formula: The formula is complex and variable, but it is often represented as C6H8O7·xFe·yNH3 or NH4[Fe(C6H4O7)2]. The exact structure depends on whether it's the green or brown form.

  Solubility: Highly soluble in water. It is insoluble in alcohol.

  Iron Content: It serves as a source of ferric iron (Fe³⁺).

  Light Sensitivity: It is photosensitive, meaning it decomposes under the influence of light. This property is the basis for its most famous historical use.

Common Uses and Applications

Ammonium ferric citrate has several important, though sometimes niche, applications:

1. Medical and Nutritional Use

This is one of its most widespread modern uses.

• Iron Supplement: It is used as a source of iron in iron tonics and dietary supplements. The iron in this compound is in a form that the body can absorb relatively easily to treat or prevent iron-deficiency anemia.

  Pharmaceutical Ingredient: It acts as an active pharmaceutical ingredient (API) in various formulations.

2. Food Additive

• In the European Union, it is listed as food additive E381, also known as Ammonium Ferric Citrate.

  Function: It is used as an acidity regulator and a iron fortification agent. You might find it added to certain foods to boost their iron content.

3. Historical and Niche Technical Uses

• Blueprint (Cyanotype) Process: This is the most famous historical use. When mixed with potassium ferricyanide and exposed to UV light, ammonium ferric citrate undergoes a photoreduction reaction. The exposed areas turn a brilliant, insoluble Prussian blue pigment after being washed in water, creating the classic cyan-blue architectural and engineering drawings known as blueprints. It is still used by artists and photographers today for this purpose.

  Animal Feed Supplement: It is sometimes added to animal feed to ensure livestock receive adequate dietary iron.

4. Industrial and Laboratory Uses

• Catalyst: It can be used as a catalyst in certain chemical reactions.

  Laboratory Reagent: It is used in various analytical chemistry procedures.

Safety and Handling

Ammonium ferric citrate is generally considered safe for consumption in regulated amounts as a supplement or food additive. However, like any chemical, it should be handled with care.

• General Safety: It can cause mild skin and eye irritation. Ingestion of large amounts can be harmful, causing gastrointestinal distress.

  Regulation: Its use in food and medicine is strictly regulated by bodies like the FDA in the US and EFSA in Europe to ensure safety.

Summary

In short, ammonium ferric citrate is a versatile chemical that bridges the worlds of medicine, food science, and art, primarily valued for its ability to deliver soluble, usable iron.