Ammonium ferric citrate

Ammonium ferric citrate
Identifiers
CAS number 1185-57-5 Y
PubChem 3080636
ChemSpider 2338386 Y
EC number 214-686-6
ChEMBL CHEMBL1200460 N
ATC code V08CA07
Jmol-3D images Image 1
Properties
Molecular formula C6H5+4yFexNyO7
Molar mass Variable
Appearance Reddish-brown powder
Hazards
MSDS ExternalMDSS
 N (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Ammonium ferric citrate is a food additive with E number E381 used as an acidity regulator. It is a green or reddish-brown powder which is very soluble in water.

The molecular formula of ammonium iron(III) citrate is variable. It can be prepared by adding Fe(OH)2 to an aqueous solution of citric acid and ammonia.[1] The brown form is approximately 9% NH3, 16.5-18.5% Fe, and 65% hydrated citric acid; the green form is approximately 7.5% NH3, 14.5-16% Fe, and 75% hydrated citric acid. The green type is more readily reduced by light than the brown.[2]

Other uses for ammonium ferric citrate include water purification and printing (cyanotype). It is used as a reducing agent of metal salts of low activity like gold and silver and is also in a commonly used recipe with potassium ferricyanide to make cyanotype prints. Ammonium ferric citrate is also used in Kligler iron deeps to determine hydrogen sulfide production in microbial metabolism.

Ammonium ferric citrate is present in Scottish carbonated soft drink Irn-Bru.[3]

In medicine, ammonium ferric citrate is used as a contrast medium. It is also used as a hematinic.[2]

Compendial status

See also

Notes