Cyanogen
Encyclopedia
Cyanogen is the chemical compound
with the formula
(C
N
)2. It is a colorless, toxic gas
with a pungent odor
.
The molecule is a pseudohalogen
. Cyanogen molecules consist of two CN groups — analogous to diatomic halogen molecules, such as Cl
2, but far less oxidizing. The two cyano
groups are bonded together at their carbon
atoms: N≡C−C≡N, although other isomers have been detected.
Certain derivatives of cyanogen are also called “cyanogen” even though they contain only one CN group. For example cyanogen bromide
has the formula NCBr.
Cyanogen is the anhydride of oxamide
:
:
Alternatively, one can combine solutions of copper(II) salts (such as copper(II) sulfate) with cyanides, an unstable copper(II) cyanide is formed which rapidly decomposes into copper(I) cyanide
and cyanogen.
Industrially, it is created by the oxidation of hydrogen cyanide, usually using chlorine
over an activated silicon dioxide
catalyst or nitrogen dioxide
over a copper
salt. It is also formed when nitrogen
and acetylene
are reacted by an electrical spark or discharge.
, who determined its empirical formula and named it. It attained importance with the growth of the fertilizer
industry in the late nineteenth century and is still an important intermediate in the production of many fertilizers. It is also used as a stabilizer in the production of nitrocellulose
.
s, cyanogen is very toxic, as it undergoes reduction to cyanide
, which binds more strongly than oxygen to the cytochrome c oxidase
complex, thus interrupting the mitochondrial
electron transfer chain. Cyanogen gas is an irritant to the eyes and respiratory system. Inhalation can lead to headache, dizziness, rapid pulse, nausea, vomiting, loss of consciousness, convulsions, and death, depending on exposure.
Cyanogen produces the second hottest known natural flame (after carbon subnitride) with a temperature of over 4525 °C when it burns in oxygen.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
(C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
N
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
)2. It is a colorless, toxic gas
Gas
Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...
with a pungent odor
Odor
An odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...
.
The molecule is a pseudohalogen
Pseudohalogen
Pseudo'halogen molecules are inorganic molecules of the general formsPs–Ps or Ps–X, where Ps is a pseudohalogen group such as cyanide, cyanate, thiocyanate and others, and X is a "true" halogen...
. Cyanogen molecules consist of two CN groups — analogous to diatomic halogen molecules, such as Cl
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
2, but far less oxidizing. The two cyano
Cyanide
A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....
groups are bonded together at their carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
atoms: N≡C−C≡N, although other isomers have been detected.
Certain derivatives of cyanogen are also called “cyanogen” even though they contain only one CN group. For example cyanogen bromide
Cyanogen bromide
Cyanogen bromide is a pseudohalogen compound with the formula CNBr. It is a colorless solid that is widely used to modify biopolymers, fragment proteins and peptides, and synthesize other compounds.-Synthesis, basic properties, and structure:...
has the formula NCBr.
Cyanogen is the anhydride of oxamide
Oxamide
Oxamide is the organic compound with the formula 2. This white crystalline solid is soluble in ethanol, slightly soluble in water and insoluble in diethyl ether...
:
- H2NC(O)C(O)NH2 → NCCN + 2 H2O
Preparation
Cyanogen is typically generated from cyanide compounds. One laboratory method entails thermal decomposition of mercuric cyanideMercury(II) cyanide
Mercury cyanide, also known as mercuric cyanide, is a coordination compound of nitrogen, carbon and mercury. It is a colorless, odorless, toxic white powder with a bitter metallic taste. It has a melting point of 320°C, at which it decomposes and releases toxic mercury fumes...
:
- 2 Hg(CN)2 → (CN)2 + Hg2(CN)2
Alternatively, one can combine solutions of copper(II) salts (such as copper(II) sulfate) with cyanides, an unstable copper(II) cyanide is formed which rapidly decomposes into copper(I) cyanide
Copper(I) cyanide
Copper cyanide in an inorganic compound with the formula CuCN. This off-white solid occurs in two polymorphs; impure samples can be green due to the presence of Cu impurities. The compound is useful as a catalyst, in electroplating copper, and as a reagent in the preparation of...
and cyanogen.
- 2 CuSO4 + 4 KCN → (CN)2 + 2 CuCN + 2 K2SO4
Industrially, it is created by the oxidation of hydrogen cyanide, usually using chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
over an activated silicon dioxide
Silicon dioxide
The chemical compound silicon dioxide, also known as silica , is an oxide of silicon with the chemical formula '. It has been known for its hardness since antiquity...
catalyst or nitrogen dioxide
Nitrogen dioxide
Nitrogen dioxide is the chemical compound with the formula it is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent...
over a copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
salt. It is also formed when nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
and acetylene
Acetylene
Acetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution.As an alkyne, acetylene is unsaturated because...
are reacted by an electrical spark or discharge.
Paracyanogen
Paracyanogen is produced by polymerization of cyanogen through pyrolysis of heavy metal cyanides.History
Cyanogen was first synthesized in 1815 by Joseph Louis Gay-LussacJoseph Louis Gay-Lussac
- External links :* from the American Chemical Society* from the Encyclopædia Britannica, 10th Edition * , Paris...
, who determined its empirical formula and named it. It attained importance with the growth of the fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
industry in the late nineteenth century and is still an important intermediate in the production of many fertilizers. It is also used as a stabilizer in the production of nitrocellulose
Nitrocellulose
Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...
.
Safety
Like other inorganic cyanideCyanide
A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....
s, cyanogen is very toxic, as it undergoes reduction to cyanide
Cyanide
A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....
, which binds more strongly than oxygen to the cytochrome c oxidase
Cytochrome c oxidase
The enzyme cytochrome c oxidase or Complex IV is a large transmembrane protein complex found in bacteria and the mitochondrion.It is the last enzyme in the respiratory electron transport chain of mitochondria located in the mitochondrial membrane...
complex, thus interrupting the mitochondrial
Mitochondrion
In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryotic cells. These organelles range from 0.5 to 1.0 micrometers in diameter...
electron transfer chain. Cyanogen gas is an irritant to the eyes and respiratory system. Inhalation can lead to headache, dizziness, rapid pulse, nausea, vomiting, loss of consciousness, convulsions, and death, depending on exposure.
Cyanogen produces the second hottest known natural flame (after carbon subnitride) with a temperature of over 4525 °C when it burns in oxygen.