Ammonium cyanide

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Ammonium cyanide
Ammonium cyanide.png
Space-filling model of the ammonium cation
Space-filling model of the cyanide anion
Identifiers
3D model (JSmol)
ChemSpider
Properties
NH4CN
Molar mass 44.0559 g/mol
Appearance colourless crystalline solid
Density 1.02 g/cm3
Boiling point 36 °C (97 °F; 309 K)
very soluble
Solubility very soluble in alcohol
Related compounds
Other anions
Ammonium hydroxide
Ammonium azide
Ammonium nitrate
Other cations
Sodium cyanide
Potassium cyanide
Related compounds
Ammonia
Hydrogen cyanide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Ammonium cyanide is an unstable inorganic compound with the formula NH4CN.

Uses[edit]

Ammonium cyanide is generally used in organic synthesis. Being unstable, it is not shipped or sold commercially.

Preparation[edit]

Ammonium cyanide is prepared in solution by bubbling hydrogen cyanide into aqueous ammonia at a low temperature

HCN + NH3(aq) → NH4CN(aq)

It may be prepared by the reaction of calcium cyanide and ammonium carbonate:

Ca(CN)2 + (NH4)2CO3 → 2 NH4CN + CaCO3

In dry state, ammonium cyanide is made by heating a mixture of potassium cyanide or potassium ferrocyanide with ammonium chloride and condensing the vapours into ammonium cyanide crystals:

KCN + NH4Cl → NH4CN + KCl

Reactions[edit]

Ammonium cyanide decomposes to ammonia and hydrogen cyanide, often forming a black polymer of hydrogen cyanide:

NH4CN → NH3 + HCN

It undergoes double decomposition reactions in solution with a number of metal salts.

It reacts with glyoxal, producing glycine (aminoacetic acid)[citation needed]:

NH4CN + (CHO)2 → NH2CH2COOH + HCN

Reactions with ketones yield aminonitriles, as in the first step of the Strecker amino acid synthesis:

NH4CN + CH3COCH3 → (CH3)2C(NH2)CN + H2O

Toxicity[edit]

The solid or its solution is highly toxic. Ingestion can cause death. Exposure to the solid can be harmful as it decomposes to highly toxic hydrogen cyanide and ammonia.

Chemical analysis[edit]

Elemental composition: H 9.15%, C 27.23%, N 63.55%.

Ammonium cyanide may be analyzed by heating the salt and trapping the decomposed products: hydrogen cyanide and ammonia in water at low temperatures. The aqueous solution is analyzed for cyanide ion by silver nitrate titrimetric method or an ion-selective electrode method, and ammonia is measured by titration or electrode technique.

Notes[edit]

References[edit]

  1. A. F. Wells, Structural Inorganic Chemistry, 5th ed., Oxford University Press, Oxford, UK, 1984.
Salts and covalent derivatives of the cyanide ion
HCN He
LiCN Be(CN)2 B C NH4CN OCN,
-NCO
FCN Ne
NaCN Mg(CN)2 Al(CN)3 SiCN P(CN)3 SCN,
-NCS,
(SCN)2,
S(CN)2
ClCN Ar
KCN Ca(CN)2 Sc(CN)3 Ti(CN)4 VO(CN)3 Cr(CN)3 Mn(CN)2 Fe(CN)3,
Fe(CN)64−,
Fe(CN)63−
Co(CN)2,
Co(CN)3
Ni(CN)2
Ni(CN)42−
CuCN Zn(CN)2 Ga(CN)3 Ge As(CN)3 SeCN
(SeCN)2
Se(CN)2
BrCN Kr
RbCN Sr(CN)2 Y(CN)3 Zr(CN)4 Nb Mo Tc Ru Rh Pd(CN)2 AgCN Cd(CN)2 In(CN)3 Sn Sb Te(CN)2,
Te(CN)4
ICN XeCN
CsCN Ba(CN)2   Hf Ta W Re Os Ir Pt Au Hg2(CN)2,
Hg(CN)2
TlCN Pb(CN)2 Bi(CN)3 Po At Rn
Fr Ra   Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
La Ce(CN)3,
Ce(CN)4
Pr Nd Pm Sm Eu Gd(CN)3 Tb Dy Ho Er Tm Yb Lu
Ac Th Pa UO2(CN)2 Np Pu Am Cm Bk Cf Es Fm Md No Lr