Sodium hexacyanidoferrate (II)

Structural formula
General
Surname	Sodium hexacyanidoferrate (II)
other names	Sodium ferrocyanide Yellow soda Sodium hexakis cyanoferrate
Molecular formula	Na 4 [Fe (CN) 6 ]
Brief description	yellow, odorless, monoclinic crystals (decahydrate)
External identifiers / databases
CAS number 13601-19-9 (decahydrate) 14434-22-1 EC number 237-081-9 ECHA InfoCard 100,033,696 PubChem 26129 ChemSpider 19957180 Wikidata Q418474
properties
Molar mass	303.91 g mol −1
Physical state	firmly
density	1.46 g cm −3
solubility	good in water (363 g l −1 at 20 ° C)
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Toxicological data	1600–3200 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Sodium hexacyanidoferrate (II) , sodium ferrocyanide or yellow soda , sodium hexakis-cyanoferrate is the sodium salt of hexacyanidoiron (II) acid with the constitutional formula Na ₄ [Fe (CN) ₆ ]. The name sodium hexacyanoferrate (II) according to the older IUPAC nomenclature is still often found .

presentation

Sodium hexacyanidoferrate (II) can be obtained by precipitating calcium carbonate from a solution of calcium hexacyanidoferrate (II) by adding soda or directly from iron (II) chloride and sodium cyanide or from iron hexacyanidoferrate (II) and sodium cyanide.

${\displaystyle \mathrm {Ca_{2}[Fe(CN)_{6}]+2\ Na_{2}CO_{3}\longrightarrow Na_{4}[Fe(CN)_{6}]+2\ CaCO_{3}} }$

${\displaystyle \mathrm {6\ NaCN+FeCl_{2}\longrightarrow Na_{4}[Fe(CN)_{6}]+2\ NaCl} }$

properties

Sodium hexacyanidoferrate is a yellow decahydrate solid with monoclinic crystals . From 81.5 ° C it is anhydrous and colorless. It is good in water and acetone , not soluble in ethanol and ether . The cyanide ions are very firmly bound to the iron (penetration complex) and are only split off by strong acids. In aqueous solution (especially in very dilute) it decomposes to a small extent in the light.

use

In the food industry it is used as a release agent (more precisely as a flow aid ) for powdered foods. In the EU , like potassium hexacyanidoferrate (II) (E 536) and calcium hexacyanidoferrate (II) (E 538), it is approved as a food additive with the number E 535 for table salt and table salt substitutes with a maximum amount limit of 20 mg / kg. Hexacyanidoferrate (II) are also used for fining wine; In the EU, of the three, only potassium hexacyanidoferrate (II) (E 536) is approved for this purpose.

Toxicity

To release the bound hydrocyanic acid z. B. gastric acid or acetic acid from foods are usually not eliminated. The substance is considered non-toxic, however, in animal experiments and in higher concentrations in humans, it shows a nephrotoxic (kidney-damaging) effect. In larger quantities it is hazardous to water.

See also

• Potassium hexacyanidoferrate (II)
• Potassium hexacyanidoferrate (III)

Individual evidence

1. ↑ ^{a b c d e f} Entry on Hexacyanidoferrate. In: Römpp Online . Georg Thieme Verlag, accessed on June 6, 2014.
2. ↑ ^{a b c} data sheet Sodium hexacyanoferrate (II) decahydrate, 99% from AlfaAesar, accessed on December 19, 2019 ( PDF )(JavaScript required) .
3. ^ Joint FAO / WHO Expert Committee on Food Additives (JECFA), Monograph for CALCIUM, POTASSIUM, SODIUM FERROCYANIDE , accessed September 15, 2015.
4. ↑ ZZulV : Appendix 4 (to Section 5, Paragraph 1 and Section 7) Limited additives