Potassium ferrocyanide trihyrate Property

Melting point:

70 °C(lit.)

Density 

1.85

storage temp. 

Store at +5°C to +30°C.

solubility 

H₂O: 0.5 M at 20 °C, clear, yellow

form 

fine crystals

color 

Yellow

Specific Gravity

1.85

Odor

Odorless

PH Range

8 - 10 at 211 g/l at 25 °C

PH

9.5 (100g/l, H2O, 20℃)(anhydrous substance)

Water Solubility 

270 g/L (12 ºC)

Merck 

14,7631

Exposure limits

ACGIH: TWA 1 mg/m3
NIOSH: IDLH 25 mg/m3; TWA 1 mg/m3

Stability:

Stable. Incompatible with oxidizing agents, stong acids (may generate very toxic HCN). Not combustible.

CAS DataBase Reference

14459-95-1(CAS DataBase Reference)

Safety

Hazard Codes 

Xn

Risk Statements 

32-20/21/22-52/53

Safety Statements 

22-24/25-36-61-47

RIDADR 

1588

WGK Germany 

2

RTECS 

LJ9219000

F 

8

TSCA 

Yes

HS Code 

28372000

Toxicity

LD50 orally in Rabbit: 3613 mg/kg

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H412Harmful to aquatic life with long lasting effects

Precautionary statements

P273Avoid release to the environment.

P501Dispose of contents/container to..…

Potassium ferrocyanide trihyrate Chemical Properties,Usage,Production

Chemical Properties

Lemon yellow monoclinic columnar crystal or powder, sometimes with cubic metamorphosis. Soluble in water, insoluble in ethanol, ether, methyl acetate and liquid ammonia.

Uses

Moderately strong oxidizer when coupled with ferricyanide. Applied in formation of a xerogel via a cyanogel the gel has potential use in solid-state gas sensors.

Uses

Potassium ferrocyanide is a yellow crystal also known as yellow prussiate of potash. It was made by stirring hot potassium carbonate with wool or horn clippings with an iron rod. It is soluble in water 1:4 but not in alcohol. Potassium ferrocyanide was used as a developer for some iron processes and as an additive for alkaline pyro developers.

Application

Potassium hexacyanoferrate(II) trihydrate may be used in the following processes:
Preparation of Carrez I solution.
Milk sample preparation for gold nanoparticles (AuNPs) based colorimetric detection of melamine.
Preparation of ferrocyanide/ferricyanide reaction, a redox pair solution for electrochemical testing.

Preparation

Potassium hexacyanoferrate(II), K4Fe(CN)6·3H20, is obtained commercially from gasworks spent oxide (which contains Prussian blue) by treatment with lime and subsequent treatment of the solution with a soluble potassium salt ; the less soluble potassium hexacyanoferrate(II) can be crystallized from this mixture. In the laboratory it is readily prepared by treating aqueous iron(II) sulphate with an excess of potassium cyanide ; the initially precipitated iron(II) cyanide dissolves upon boiling in the excess of potassium cyanide solution and the ferrocyanide crystallizes on cooling.

General Description

Potassium hexacyanoferrate(II) trihydrate, commonly known as potassium ferrocyanide, is a commonly used anticaking agent. Its cytotoxic and genotoxic effect has been evaluated. The growth of chemical garden in aqueous potassium hexacyanoferrate solution droplets on a superhydrophobic surface has been reported. The inhibition efficiency of potassium ferrocyanide in phosphoric acid solution against the corrosion of mild steel has been investigated.

Purification Methods

The anhydrous salt is prepared by drying at 110o over P2O5 in a vacuum desiccator. To obtain the trihydrate, it is necessary to equilibrate the salt in a desiccator over a saturated aqueous solution of sucrose and NaCl. It can also be precipitated from a saturated solution at 0o by adding an equal volume of cold 95% EtOH, setting aside for several hours, then centrifuge and wash with cold 95% EtOH. It is finally sucked air dry with water-pump vacuum. The anhydrous salt is obtained by drying the hydrate in a platinum boat at 90o in a slow stream of N2 [Loftfield & Swift J Am Chem Soc 60 3083 1938].

Structure and conformation

The trihydrate is diamagnetic and dimorphic existing in monoclinic (pseudotetragonal) and tetragonal forms. Its infrared spectrum in solution shows a single ν(C≡ N) at 2044 cm^-1, but in the solid state a large number of bands are observed160; ν(Fe-C) occurs at 416cm^-1. White, anhydrous K4Fe(CN)6 is obtained by dehydrating the trihydrate at 100°.