Sodium ferrocyanide

• Sodium ferrocyanide
• Gelbnatron
• Sodium hexakis hexacyanoferrate

Yellow, monoclinic crystals ( decahydrate )

Fixed

1.46 g · cm -3

Well in water ( 319 g · l-1 at 20 ° C)

5 mg · m -3 ( cyanide)

Template: Infobox chemical / molecular formula search available

Natriumhexacyanidoferrat (II), sodium ferrocyanide or Gelbnatron, hexakis sodium hexacyanoferrate is the sodium salt of Hexacyanidoeisen (II ) acid with the structural formula Na4 [Fe (CN ) 6]. It still often find the name Natriumhexacyanoferrat (II ) according to the IUPAC nomenclature older. It is well water and acetone, insoluble in ethanol and ether. The cyanide ions are very tightly bound to the iron ( Durchdringungskomplex ) and are only cleaved 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 for powdered foods as a release agent (specifically, as a flow aid ). In the EU, it is as well Kaliumhexacyanidoferrat (II ) (E 536) and Calciumhexacyanidoferrat (II ) (E 538 ) as a food additive under the number E 535 approved for table salt and salt substitutes with a maximum limit of a maximum of 20 mg / kg. In addition Hexacyanidoferrate (II ) are used for the fining of wine; in the EU only the Kaliumhexacyanidoferrat (II ) (E 536) is of the three, however, admitted this.

Toxicity

To release the bound cyanide rich example the stomach acid or acetic acid not from foods usually. In animal experiments and in higher concentrations in humans it shows a nephrotoxic ( kidney damaging ) effect.