Sodium hexacyanoferrate (II)

Sodium hexacyanoferrate(II) ;
Names:	sodium hexacyanoferrate(II); sodium hexacyanoferroate; sodium cyanoferrate; sodium ferrocyanide; yellow prussiate of soda; gelbnatron; Е535 food additive;
Formula:	Na4[Fe(CN)6] (anhydrous); Na4[Fe(CN)6] · 10H2O (decahydrate);
Molar mass:	303.913 g/mol (anhydrous); 484.062 g/mol (decahydrate);
Density:	1.458 g/cm3 (anhydrous); 1.329 g/cm3 (decahydrate);
Crystal system:	monoclinic (decahydrate); α=90°, γ=90°;
Shapes:	https://en.crystalls.info/w/uploads/media/a/a8/Rhombic_dodecahedron.json Rhombic dodecahedron ;
Color:	bright-yellow;
Melting point:	650 °C923.15 K <br />1,202 °F <br />1,661.67 °R <br /> (anhydrous);
Refractive index:	1.531 (decahydrate);
Magnetic properties:	diamagnetic;
Stability:	slightly erodes (decahydrate);
Hardness:	relatively strong;
Toxicity:	non-toxic; LD50=2500mg/kg

Description

Inorganic complex compound, salt of alkaline metal sodium and inorganic ferrocyanide acid. From water solutions crystallizes as decahydrate.

Precursors

Reaction between potassium ferrocyanide, hydrochloric acid and sodium hydroxide

Chemical equation:

K₄[Fe(CN)₆] + 4HCl = H₄[Fe(CN)₆]↓ + 4KCl

H₄[Fe(CN)₆] + 4NaOH = Na₄[Fe(CN)₆] + 4H₂O

For preparation of 100.00g of sodium hexacyanoferrate(II)

decahydratedecahydrate
anhydrous

а 87.26g of potassium ferrocyanide

trihydratetrihydrate
anhydrous

and 33.05g of sodium hydroxide or 81.43g of 37%37% hydrochloric acid is required.

Add to the flask with potassium ferrocyanide solution small parts of hydrochloric acid solution and stir. The large amount of poorly soluble precipitate will form. Settle it out and wash it from soluble impurities few times.Add to flask with hot concentrated solution of sodium hydroxide small amount of that precipitate with intense stirring. Heat it to 100°C for few minutes for reaction completion and then filter out. For purifying compound from hydroxide add large amount of cold ethanol, acetone or toluene to solution, salt will settle to the bottom in the form of fine crystals or powder. Filter precipitate and wash it with small amount of the same solvent, then filter the solution and use it for crystal growing.

Reaction between prussian blue and sodium hydroxide

Chemical equation:

Fe₄[Fe(CN)₆]₃ + 12NaOH = 3Na₄[Fe(CN)₆] + 4Fe(OH)₃↓

For preparation of 100.00g of sodium hexacyanoferrate(II)

decahydratedecahydrate
anhydrous

а 33.05g of sodium hydroxide and 59.17g of prussian blue is required.

Add to flask with prussian blue small amount of water until it will become a thick slurry. Then add small parts of diluted hydroxide solution with intense stirring. Mixture will change color from dark-blue to dark-brown, become more homogeneous and could even boils because of exothermic. Heat it to 100°C for few minutes for reaction completion, filter out a precipitation of iron hydroxide.

Reaction between potassium ferrocyanide and sodium cation-exchange resin

Chemical equation:

K₄[Fe(CN)₆] + 4Na⁺ = Na₄[Fe(CN)₆] + 4K⁺

For preparation of 100.00g of sodium hexacyanoferrate(II)

decahydratedecahydrate
anhydrous

а 73.95g of potassium ferrocyanide

trihydratetrihydrate
anhydrous

is required.

Add warm potassium ferrocyanide solution to chemical column with sodium cation exchange resin and shake it.

Influence of temperature

Growing at higher temperature gives mostly polycrystalline.

Notes

Slowly reacts with diluted sulfuric acid with poisonous hydrocyanic acid emission, so be careful. Concentrated acid decomposes it to carbon monoxide, another ones gives participate of ferrocyanide acid.

Storage conditions

Store in its original form or under several layers of varnish at average humidity and room temperature. Do not store in matchboxes or cotton wool and do not heat.

Solubility

TableGraph

Temperature	гр/`100,00` гр water
Temperature	(anhydrous)	(decahydrate)
0°C273.15 K <br />32 °F <br />491.67 °R <br />	`~11.4`	`~17.3`
20°C293.15 K <br />68 °F <br />527.67 °R <br />	`17.9`	`31.85`
25°C298.15 K <br />77 °F <br />536.67 °R <br />	`20.725`	`~38.8`
30°C303.15 K <br />86 °F <br />545.67 °R <br />	`23.5`	`~43.5`
40°C313.15 K <br />104 °F <br />563.67 °R <br />	`30.2`	`~58.6`
60°C333.15 K <br />140 °F <br />599.67 °R <br />	`42.5`	`~90.5`
80°C353.15 K <br />176 °F <br />635.67 °R <br />	`59.2`	`~145.3`
100°C373.15 K <br />212 °F <br />671.67 °R <br />	`63`	`156.5`

Insoluble in ethanol, methanol, acetone, diethyl ether, toluene, aniline, pyridine, ethyl acetate and isopropanol.

Gallery

Sources

Navigation

Cyanides
Hexacyanoferroates	Potassium hexacyanoferrate(II) (K₄[Fe(CN)₆]) • Sodium hexacyanoferrate(II) (Na₄[Fe(CN)₆]) • Tripotassium-sodium hexacyanoferrate(II) (K₃Na[Fe(CN)₆])
Hexacyanoferriates	Potassium hexacyanoferrate(III) (K₃[Fe(CN)₆])
Hexacyanocobaltates	Potassium hexacyanocobaltate(III) (K₃[Co(CN)₆])
Hexacyanochromates	Potassium hexacyanochromate(III) (K₃[Cr(CN)₆])
Nitroprussides	Sodium nitroprusside (Na₂[Fe(CN)₅NO])
Complexes	Cyanocobalamin (C₆₃H₈₈CoN₁₄O₁₄P)

Sodium compounds
Salts	Sodium acetate (NaCH₃COO) • Sodium bromide (NaBr) • Sodium citrate (Na₃C₃H₅O(COO)₃) • Sodium chlorate (NaClO₃) • Sodium chloride (NaCl) • Sodium cyclamate (C₆H₁₂NNaO₃S) • Sodium decavanadate (Na₆V₁₀O₂₈) • Sodium ethilate (NaC₂H₅O) • Sodium glutamate (NaC₅H₈NO₄) • Sodium hydrocarbonate (NaHCO₃) • Sodium hydrosulfate (NaHSO₄) • Sodium iodide (NaI) • Sodium metavanadate (NaVO₃) • Sodium niobate (NaNbO₃) • Sodium nitrate (NaNO₃) • Sodium oxalate (Na₂C₂O₄) • Sodium para-aminosalicylate (C₇H₆NNaO₃) • Sodium perchlorate (NaClO₄) • Sodium saccharinate (C₇H₄NaNO₃S) • Sodium sulfate (Na₂SO₄) • Sodium sulfide (Na₂S) • Sodium tetraborate (Na₂B₄O₇) • Sodium thiosulfate (Na₂S₂O₃) • Sodium trichloracetate (NaCCl₃COO) • Sodium trioxalatoaluminate (Na₃[Al(C₂O₄)₃]) • Sodium tungstate (Na₂WO₄)
Double salts	Potassium-sodium tartrate (KNaC₄H₄O₆) • Sodium-ammonium sulfate (NaNH₄SO₄) • Uranyl-sodium acetate (NaUО2(CH₃COO)₃) • Uranyl-zinc-sodium acetate (NaZn(UO₂)₃(CH₃COO)₉) • Zinc-sodium sulfate (Na₂Zn(SO₄)₂)
Adducts	Glucose and sodium bromide complex (2C₆H₁₂O₆ · NaBr) • Glucose and sodium chloride complex (2C₆H₁₂O₆ · NaCl) • Urea and sodium chloride complex (CO(NH₄)₂ · NaCl)
Complex compounds	Sodium dicarbonatocuprate(II) (Na₂[Cu(CO₃)₂]) • Sodium dioxalatocuprate(II) (Na₂[Cu(C₂O₄)₂]) • Sodium ethylenediaminetetraacetate-ferrate(III) (Na[Fe((OOCCH₂)₂N(CH₂)₂N(CH₂COO)₂)]) • Sodium hexacyanoferrate(II) (Na₄[Fe(CN)₆]) • Tripotassium-sodium hexacyanoferrate(II) (K₃Na[Fe(CN)₆]) • Sodium hexafluorosilicate (Na₂[SiF₆]) • Sodium nitroprusside (Na₂[Fe(CN)₅NO]) • Sodium trioxalatochromate(III) (Ns₃[Cr(C₂O₄)₃]) • Dipotassium-sodium trioxalatoferrate(III) (K₂Na[Fe(C₂O₄)₃]) • Potassium-sodium trioxalatoferrate(III) (K₅Na[Fe(C₂O₄)₃]₂) • Sodium trioxalatoferrate(III) (Na₃[Fe(C₂O₄)₃])

Sodium hexacyanoferrate(II)
Names:	sodium hexacyanoferrate(II) sodium hexacyanoferroate sodium cyanoferrate sodium ferrocyanide yellow prussiate of soda gelbnatron Е535 food additive
Formula:	Na₄[Fe(CN)₆] (anhydrous) Na₄[Fe(CN)₆] · 10H₂O (decahydrate)
Molar mass:	303.913 g/mol (anhydrous) 484.062 g/mol (decahydrate)
Density:	1.458 g/cm³ (anhydrous) 1.329 g/cm³ (decahydrate)
Crystal system:	monoclinic (decahydrate) α=90°, γ=90°
Shapes:	Rhombic dodecahedron
Color:	bright-yellow
Melting point:	650 °C923.15 K <br />1,202 °F <br />1,661.67 °R <br /> (anhydrous)
Refractive index:	1.531 (decahydrate)
Magnetic properties:	diamagnetic
Stability:	slightly erodes (decahydrate)
Hardness:	relatively strong
Toxicity:	non-toxic LD₅₀=2500mg/kg