Nitrogen trichloride
Encyclopedia
Nitrogen trichloride, also known as trichloramine, is the chemical compound
with the formula
NCl3. This yellow, oily, pungent-smelling liquid is most commonly encountered as a byproduct of chemical reaction
s between ammonia
-derivatives and chlorine
(for example, in swimming pool
s between disinfecting chlorine and urea
in urine from bathers).
In pure form, NCl3 is highly reactive. Nitrogen trichloride can form in small amounts when public water supplies are disinfected with monochloramine, and at given levels it can irritate mucous membranes. Nitrogen trichloride was trademarked as Agene and used to artificially bleach and age flour
. It has the same effect as that of tear gas
, but has never been used as such.
Intermediates in this conversion include chloramine
and dichloramine
, NH2Cl and NHCl2, respectively.
Like ammonia, NCl3 is a pyramidal molecule. The N-Cl distances are 1.76 Å, and the Cl-N-Cl angles are 107°. The Pauling electronegativities
are very similar for nitrogen (3.04) and chlorine (3.16).
Nitrogen trichloride is hydrolyzed by hot water to release ammonia
and hypochlorous acid
.
first prepared it in 1812, and lost two fingers and an eye in two separate explosions. An explosion from NCl3 blinded Sir Humphry Davy
temporarily, inducing him to hire Michael Faraday
as a co-worker.
In 2006, Belgian researchers reported a possible link between NCl3 and rising numbers of childhood asthma
cases, in what they call the pool chlorine hypothesis
, as an alternative to the hygiene hypothesis
with a closer causal link.
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....
NCl3. This yellow, oily, pungent-smelling liquid is most commonly encountered as a byproduct of chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
s between ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
-derivatives and 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...
(for example, in swimming pool
Swimming pool
A swimming pool, swimming bath, wading pool, or simply a pool, is a container filled with water intended for swimming or water-based recreation. There are many standard sizes; the largest is the Olympic-size swimming pool...
s between disinfecting chlorine and urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....
in urine from bathers).
In pure form, NCl3 is highly reactive. Nitrogen trichloride can form in small amounts when public water supplies are disinfected with monochloramine, and at given levels it can irritate mucous membranes. Nitrogen trichloride was trademarked as Agene and used to artificially bleach and age flour
Flour
Flour is a powder which is made by grinding cereal grains, other seeds or roots . It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...
. It has the same effect as that of tear gas
Lachrymatory agent
Tear gas, formally known as a lachrymatory agent or lachrymator , is a non-lethal chemical weapon that stimulates the corneal nerves in the eyes to cause tears, pain, and even blindness...
, but has never been used as such.
Preparation and structure
The compound is prepared by treatment of ammonium salts, such as ammonium nitrate with chlorine:- 4 NH3 + 3 Cl2 → NCl3 + 3 NH4Cl
Intermediates in this conversion include chloramine
Chloramine
Chloramines are derivatives of ammonia by substitution of one, two or three hydrogen atoms with chlorine atoms. Monochloramine is an inorganic compound with the formula NH2Cl. It is an unstable colourless liquid at its melting point of -66° temperature, but it is usually handled as a dilute...
and dichloramine
Dichloramine
Dichloramine is a reactive inorganic compound. It has the formula . The yellow gas is unstable and reacts with many materials. It is formed by a reaction between ammonia and chlorine or sodium hypochlorite...
, NH2Cl and NHCl2, respectively.
Like ammonia, NCl3 is a pyramidal molecule. The N-Cl distances are 1.76 Å, and the Cl-N-Cl angles are 107°. The Pauling electronegativities
Electronegativity
Electronegativity, symbol χ , is a chemical property that describes the tendency of an atom or a functional group to attract electrons towards itself. An atom's electronegativity is affected by both its atomic number and the distance that its valence electrons reside from the charged nucleus...
are very similar for nitrogen (3.04) and chlorine (3.16).
Reactions
The nitrogen in NCl3 is often considered to have the -3 oxidation state and the chlorine atoms are considered to be in the +1 oxidation state. Most of its reactivity is consistent with this description.Nitrogen trichloride is hydrolyzed by hot water to release ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
and hypochlorous acid
Hypochlorous acid
Hypochlorous acid is a weak acid with the chemical formula HClO. It forms when chlorine dissolves in water. It cannot be isolated in pure form due to rapid equilibration with its precursor...
.
- NCl3 + 3 H2O → NH3 + 3 HOCl
Safety
Nitrogen trichloride is a dangerous explosive, being sensitive to light, heat, even moderate shock, and organic compounds. Pierre Louis DulongPierre Louis Dulong
Pierre Louis Dulong was a French physicist and chemist, remembered today largely for the law of Dulong and Petit. He worked on the specific heat capacity and the expansion and refractive indices of gases....
first prepared it in 1812, and lost two fingers and an eye in two separate explosions. An explosion from NCl3 blinded Sir Humphry Davy
Humphry Davy
Sir Humphry Davy, 1st Baronet FRS MRIA was a British chemist and inventor. He is probably best remembered today for his discoveries of several alkali and alkaline earth metals, as well as contributions to the discoveries of the elemental nature of chlorine and iodine...
temporarily, inducing him to hire Michael Faraday
Michael Faraday
Michael Faraday, FRS was an English chemist and physicist who contributed to the fields of electromagnetism and electrochemistry....
as a co-worker.
In 2006, Belgian researchers reported a possible link between NCl3 and rising numbers of childhood asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
cases, in what they call the pool chlorine hypothesis
Pool chlorine hypothesis
The pool chlorine hypothesis is the hypothesis that long-term attendance at indoor chlorinated swimming pools by children up to the age of about 6-7 years is a major factor in the rise of asthma in rich countries since the late twentieth century. A narrower version of the hypothesis, i.e...
, as an alternative to the hygiene hypothesis
Hygiene hypothesis
In medicine, the Hygiene Hypothesis states that a lack of early childhood exposure to infectious agents, symbiotic microorganisms , and parasites increases susceptibility to allergic diseases by suppressing natural development of the immune system...
with a closer causal link.