Ammonium ferric citrate (also known as Ferric Ammonium Citrate or Ammoniacal ferrous citrate) has the formula (NH
4)
5 6H4O7)2">e(C6H4O7)2 A distinguishing feature of this compound is that it is very soluble in water, in contrast to
ferric citrate which is not very soluble.
In its crystal structure each
moiety
Moiety may refer to:
Chemistry
* Moiety (chemistry), a part or functional group of a molecule
** Moiety conservation, conservation of a subgroup in a chemical species
Anthropology
* Moiety (kinship), either of two groups into which a society is ...
of
citric acid
Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in ...
has lost four protons. The deprotonated hydroxyl group and two of the carboxylate groups ligate to the ferric center, while the third carboxylate group coordinates with the ammonium.
[
]
Uses
Ammonium ferric citrate has a range of uses, including:
* As a food ingredient, it has an
INS number 381, and is used as an
acidity regulator. Most notably used in the Scottish beverage
Irn-Bru
Irn-Bru ( "iron brew", ) is a Scottish carbonated soft drink, often described as "Scotland's other national drink" (after whisky). Introduced in 1901, the drink is produced in Westfield, Cumbernauld, North Lanarkshire, by A.G. Barr of Glasgo ...
.
* Water purification
* As a reducing agent of metal salts of low activity like gold and
silver
Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...
* With
potassium ferricyanide
Potassium ferricyanide is the chemical compound with the formula K3 e(CN)6 This bright red salt contains the octahedrally coordinated 3−.html" ;"title="e(CN)6sup>3−">e(CN)6sup>3− ion. It is soluble in water and its solution shows some g ...
as part of the
cyanotype
The cyanotype (from Ancient Greek κυάνεος - ''kuáneos'', “dark blue” + τύπος - ''túpos'', “mark, impression, type”) is a slow-reacting, economical photographic printing formulation sensitive to a limited near ultraviolet ...
photographic process
* Used in
Kligler's Iron Agar (KIA) test to identify
enterobacteriaceae bacteria by observing their metabolism of different sugars, producing
hydrogen sulfide
* In medical imaging, ammonium ferric citrate is used as a
contrast medium
A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radio ...
.
* As a
hematinic
A hematinic is a nutrient required for the formation of blood cells in the process of hematopoiesis. The main hematinics are iron, B12, and folate. Deficiency in hematinics can lead to anaemia. In cases of hematinic deficiency, hematinics can be ...
See also
*
Food additive
*
List of food additives
Food additives are substances added to food to preserve flavor or enhance its taste, appearance, or other qualities.
Purposes
Additives are used for many purposes but the main uses are:
;Acids : Food acids are added to make flavors "sharper", ...
References
{{DEFAULTSORT:Ammonium Ferric Citrate
Ammonium compounds
Citrates
Iron(III) compounds
MRI contrast agents
Photographic chemicals
Double salts