Ammonium iron (III) sulfate

Structural formula
${\displaystyle \mathrm {\ {\Biggl [}} }$ ${\displaystyle \mathrm {\ \!\ {\Biggr ]}_{2}} }$
General
Surname	Ammonium iron (III) sulfate
other names	Ammonium iron alum Iron alum Iron ammonium alum
Molecular formula	NH 4 Fe (SO 4 ) 2 NH 4 Fe (SO 4 ) 2 • 12 H 2 O
Brief description	colorless solid, often pale purple due to traces of manganese
External identifiers / databases
CAS number 10138-04-2 7783-83-7 (dodecahydrate) EC number 233-382-4 ECHA InfoCard 100.030.335 PubChem 53393738 ChemSpider 55405 Wikidata Q421435
properties
Molar mass	266.00 g mol −1 anhydrous 482.19 g mol −1 dodecahydrate
Physical state	firmly
density	1.71 g cm −3
Melting point	39-41 ° C
solubility	very good in water (1240 g l −1 at 25 ° C)
safety instructions
GHS labeling of hazardous substances Dodecahydrate Caution H and P phrases H: 315-319 P: 280-305 + 351 + 338-302 + 352-321-362-332 + 313
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Ammonium iron (III) sulfate , is a salt consisting of iron , ammonium and sulfate ions . It has the formula NH ₄ Fe (SO ₄ ) ₂ .

properties

The ammonium iron (III) sulfate dodecahydrate, which belongs to the group of alums, forms water-soluble, pale purple cubic crystals with a density of 1.71 g / cm ³ and a molar mass of 482.19 g / mol. The melting point is between 39 and 41 ° C. When heated from 230 ° C, it changes into the anhydrous form NH ₄ Fe (SO ₄ ) ₂ with a molar mass of 266.00. In solution , the Berlin blue is formed with potassium hexacyanoferrate (II) , the yellow blood liquor salt .

use

Ammonium iron (III) sulfate dodecahydrate is used as an indicator for titrations according to Volhard . It is also used as a stain in the textile industry and as an astringent in medicine .

Ammonium iron (III) sulfate dodecahydrate

Individual evidence

1. ↑ ^{a b} Entry on ammonium iron (III) sulfate. In: Römpp Online . Georg Thieme Verlag, accessed on June 27, 2014.
2. ↑ ^{a b c d} data sheet ammonium iron (III) sulfate from AlfaAesar, accessed on February 1, 2012 ( PDF )(JavaScript required) .