Potassium hexacyanoferrate(III)

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Crystal compoundsSaltsCyanidesPotassium hexacyanoferrate(III)


  Potassium hexacyanoferrate(III)   
Names: potassium hexacyanoferrate(III)
potassium hexacyanoferriate
potassium cyanoferrite
potassium ferricyanide
red prussiate of potash
prussian red

Formula: K3[Fe(CN)6]
SMILES: [C-]#N.[C-]#N.[C-]#N.[C-]#N.[C-]#N.[C-]#N.[K+].[K+].[K+].[Fe+3]
Molar mass: 329.247 g/mol
Density: 1.845 g/cm3
Crystal system: monoclinic (α)
a=7.058 Å
7.0580 Å
0.7058 nm
, b=10.426 Å
10.4260 Å
1.0426 nm
, c=8.401 Å
8.4010 Å
0.8401 nm
α=90°
90°  
, β=107.311°
107°18′39.6″  
, γ=90°
90°  

monoclinic (β)
a=14.021 Å
14.0210 Å
1.4021 nm
, b=10.401 Å
10.4010 Å
1.0401 nm
, c=8.339 Å
8.3390 Å
0.8339 nm
α=90°
90°  
, β=107.21°
107°12′36.0″  
, γ=90°
90°  

orthorhombic (γ)
a=13.4226 Å
13.4226 Å
1.3423 nm
, b=10.3964 Å
10.3964 Å
1.0396 nm
, c=8.3814 Å
8.3814 Å
0.8381 nm
α=90°
90°  
, β=90°
90°  
, γ=90°
90°  

Forms:
https://media.crystalls.info/w/uploads/media/Prolongated_tetragonal_pyramidal_prism.json
https://media.crystalls.info/w/uploads/media/Prolongated_rhombic_prism.json
https://media.crystalls.info/w/uploads/media/Prolongated_hexagonal_prism.json
https://media.crystalls.info/w/uploads/media/Truncated_prolongated_hexagonal_bipyramid.json
https://media.crystalls.info/w/uploads/media/Truncated_prolongated_hexagonal_pyramid.json

Color: dark-red
Melting point: 300 °C
573.15 K
572 °F
1,031.67 °R

Decomposition point: -173.15 °C
100 K
-279.67 °F
180 °R
(α)
Refractive index: 1.573
Magnetic properties: paramagnetic
χ=0.000229 cm³/mol
Hardness: relatively strong
Toxicity: poisonous

Description

Inorganic complex compound, salt of alkaline metal potassium and inorganic ferricyanide acid. Doesn`t form water hydrates.

Precursors

Reaction between potassium ferrocyanide, hydrogen peroxide and sulfuric or hydrochloric acid

Chemical equation:

2K4[Fe(CN)6] + H2O2 + H2SO4 = 2K3[Fe(CN)6] + K2SO4 + 2H2O
2K4[Fe(CN)6] + H2O2 + 2HCl = 2K3[Fe(CN)6] + 2KCl + 2H2O

For preparation of 100.00g of potassium hexacyanoferrate(III) а 128.29g of potassium ferrocyanide trihydrate, 172.18g of 3% peroxide and 40.25g of 37% sulfuric or 29.93g of 37% hydrochloric acid is required.
Add to the flask with potassium ferrocyanide solution hydrogen peroxide and then add small parts of acid with stirring until a precipitation forming will stop. For purifying compound from potassium salts add large amount of cold ethanol, isopropanol 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.

Influence of temperature

While temperature increasing or decreasing rapidly, strokes could be formed at crystal faces.
Growing at higher temperature gives mostly polycrystalline.

Influence of impurities

Opacity of crystals is increasing with compound impurity.

Notes

At sunlight and air oxygen solution decomposes with forming green precipitate which impairs growth. So make as saturated solution as possible and do not use if for growth for a long time-every next crystallization layer will become more dirty and deformed.
Reacts with acids with hydrocyanic acid emission.

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

Temperatureгр/100,00 гр waterгр/100,00 гр methanolгр/100,00 гр hydrazineгр/100,00 гр dimethylformamideгр/100,00 гр formamide
0°C
273.15 K
32 °F
491.67 °R
29.9
29.9 g/100g
23.018 %
10°C
283.15 K
50 °F
509.67 °R
38.3
38.3 g/100g
27.693 %
15°C
288.15 K
59 °F
518.67 °R
~42.4
42.4 g/100g
29.775 %
20°C
293.15 K
68 °F
527.67 °R
46.4
46.4 g/100g
31.694 %
2
2 g/100g
1.961 %
25°C
298.15 K
77 °F
536.67 °R
48.8
48.8 g/100g
32.796 %
0.05
0.05 g/100g
0.05 %
2.7
2.7 g/100g
2.629 %
30°C
303.15 K
86 °F
545.67 °R
52.7
52.7 g/100g
34.512 %
40°C
313.15 K
104 °F
563.67 °R
59.5
59.5 g/100g
37.304 %
50°C
323.15 K
122 °F
581.67 °R
~65.2
65.2 g/100g
39.467 %
60°C
333.15 K
140 °F
599.67 °R
70.9
70.9 g/100g
41.486 %
70°C
343.15 K
158 °F
617.67 °R
77.5
77.5 g/100g
43.662 %
0.31
0.31 g/100g
0.309 %
80°C
353.15 K
176 °F
635.67 °R
81.8
81.8 g/100g
44.994 %
90°C
363.15 K
194 °F
653.67 °R
~86.7
86.7 g/100g
46.438 %
100°C
373.15 K
212 °F
671.67 °R
91.6
91.6 g/100g
47.808 %
Insoluble in ethanol, acetone, diethyl ether, toluene, aniline, pyridine, ethyl acetate and isopropanol.

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