BleedingLips
August 6th, 2002, 08:05 AM
February 2, 1999
New Nitrogen Ion Carries Warning: Handle With Care
By MALCOLM W. BROWNE
For a century, chemists doubted that such a substance could exist, but
scientists at an Air Force laboratory have created a freakish form of
nitrogen believed to be one of the most violently explosive substances ever
made.
To the acclaim of many other scientists, a team of chemists headed by Dr.
Karl O. Christe and Dr. William W. Wilson at the Air Force Research
Laboratory at Edwards Air Force Base, Calif., reported their achievement
at a recent meeting of the American Chemical Society.
The new compound is a positively charged ion, or molecular fragment,
consisting of five nitrogen atoms chemically bonded to each other in a V
pattern. It is so sensitive and explosive, the magazine Chemical &
Engineering News reported, that a few tiny grains of the substance
accidentally detonated, destroying part of the apparatus being used to
analyze it.
The newly synthesized allotrope, or form, of nitrogen (N5 ) is only the
third such form of the element ever discovered.
Nitrogen in its most common, gaseous form, consisting of two atoms of
the element chemically bound to each other (N2 ), makes up four fifths of
the earth's atmosphere and is quite stable and chemically unreactive. This
form of nitrogen was identified in 1772.
The next allotrope of nitrogen to be discovered was the azide ion (N3 ),
containing three bound nitrogen atoms, which was synthesized in 1890.
Azides combined with metals as salts are unstable and explosive; lead
azide, for example, has been used commercially to detonate high
explosives, and sodium azide is the explosive used to inflate automobile air
bags.
To chemically bind increasing numbers of nitrogen atoms to one another
requires enormous energy, and chemical theorists had predicted that
nitrogen allotropes with more than three nitrogen atoms would be so
unstable they could not exist.
Dr. Christe's team, however, has confounded the experts.
Over four months, his group succeeded in synthesizing a salt in which the
positive ion consists of five nitrogen atoms and the negative ion consists of
an arsenic atom with six fluorine atoms. The group obtained proof of the
substance's chemical composition using laser spectroscopy, but after the
analysis was completed, several grains of the white crystalline powder
exploded, demolishing the sample chamber.
The material is so dangerous to handle that only a handful of laboratories
would be able to perform Dr. Christe's synthesis, chemists said.
Dr. Steven H. Strauss of Colorado State University at Fort Collins, who is
familiar with Dr. Christe's work, said in an interview that even the most
experienced chemists regard the synthesis of an allotrope with five nitrogen
atoms as astonishing.
"Just having shown that this substance can exist even temporarily is a
gigantic achievement," he said. "Theorists who may have considered this
type of compound impossible will have to do some recalculating."
Dr. Christe is known for another tour de force in chemistry: the first
successful separation, in 1986, of pure fluorine from a fluorine compound
using chemical reactions alone. Fluorine, a poisonous pale yellow gas, is
normally prepared by passing a current of electricity through molten
fluoride salts. Fluorine is the most violently reactive of all elements, and it
can be separated from its compounds only with the help of large amounts
of energy. Most chemists had believed that chemical separation of
elemental fluorine was probably impossible.
Dr. Christe works at the propulsion division of the Air Force laboratory at
Edwards Air Force Base, and his research, some of it secret, is financed
by the Air Force, the Defense Advanced Research Projects Agency and
the National Science Foundation.
He said in an interview that the new nitrogen allotrope was likely to find
uses, but he declined to say what they would be. However, the material is
such a powerful oxidizing agent that it explosively rips water molecules
apart.
Dr. Christe said that the latest goal of his group was to synthesize an
all-nitrogen salt consisting of a positive ion of five nitrogen atoms bound to
a negative ion of five nitrogen atoms. Such a compound, containing 10
mutually linked nitrogen atoms, would be extremely difficult if not
impossible to synthesize, but it would probably pack stupendous chemical
energy that might be released with great explosive force.
Interesting links:
<a href="http://www.llnl.gov/str/June01/Manaa.html" target="_blank">http://www.llnl.gov/str/June01/Manaa.html</a>
<a href="http://www-cms.llnl.gov/buckyballs/research_proj.html" target="_blank">http://www-cms.llnl.gov/buckyballs/research_proj.html</a>
New Nitrogen Ion Carries Warning: Handle With Care
By MALCOLM W. BROWNE
For a century, chemists doubted that such a substance could exist, but
scientists at an Air Force laboratory have created a freakish form of
nitrogen believed to be one of the most violently explosive substances ever
made.
To the acclaim of many other scientists, a team of chemists headed by Dr.
Karl O. Christe and Dr. William W. Wilson at the Air Force Research
Laboratory at Edwards Air Force Base, Calif., reported their achievement
at a recent meeting of the American Chemical Society.
The new compound is a positively charged ion, or molecular fragment,
consisting of five nitrogen atoms chemically bonded to each other in a V
pattern. It is so sensitive and explosive, the magazine Chemical &
Engineering News reported, that a few tiny grains of the substance
accidentally detonated, destroying part of the apparatus being used to
analyze it.
The newly synthesized allotrope, or form, of nitrogen (N5 ) is only the
third such form of the element ever discovered.
Nitrogen in its most common, gaseous form, consisting of two atoms of
the element chemically bound to each other (N2 ), makes up four fifths of
the earth's atmosphere and is quite stable and chemically unreactive. This
form of nitrogen was identified in 1772.
The next allotrope of nitrogen to be discovered was the azide ion (N3 ),
containing three bound nitrogen atoms, which was synthesized in 1890.
Azides combined with metals as salts are unstable and explosive; lead
azide, for example, has been used commercially to detonate high
explosives, and sodium azide is the explosive used to inflate automobile air
bags.
To chemically bind increasing numbers of nitrogen atoms to one another
requires enormous energy, and chemical theorists had predicted that
nitrogen allotropes with more than three nitrogen atoms would be so
unstable they could not exist.
Dr. Christe's team, however, has confounded the experts.
Over four months, his group succeeded in synthesizing a salt in which the
positive ion consists of five nitrogen atoms and the negative ion consists of
an arsenic atom with six fluorine atoms. The group obtained proof of the
substance's chemical composition using laser spectroscopy, but after the
analysis was completed, several grains of the white crystalline powder
exploded, demolishing the sample chamber.
The material is so dangerous to handle that only a handful of laboratories
would be able to perform Dr. Christe's synthesis, chemists said.
Dr. Steven H. Strauss of Colorado State University at Fort Collins, who is
familiar with Dr. Christe's work, said in an interview that even the most
experienced chemists regard the synthesis of an allotrope with five nitrogen
atoms as astonishing.
"Just having shown that this substance can exist even temporarily is a
gigantic achievement," he said. "Theorists who may have considered this
type of compound impossible will have to do some recalculating."
Dr. Christe is known for another tour de force in chemistry: the first
successful separation, in 1986, of pure fluorine from a fluorine compound
using chemical reactions alone. Fluorine, a poisonous pale yellow gas, is
normally prepared by passing a current of electricity through molten
fluoride salts. Fluorine is the most violently reactive of all elements, and it
can be separated from its compounds only with the help of large amounts
of energy. Most chemists had believed that chemical separation of
elemental fluorine was probably impossible.
Dr. Christe works at the propulsion division of the Air Force laboratory at
Edwards Air Force Base, and his research, some of it secret, is financed
by the Air Force, the Defense Advanced Research Projects Agency and
the National Science Foundation.
He said in an interview that the new nitrogen allotrope was likely to find
uses, but he declined to say what they would be. However, the material is
such a powerful oxidizing agent that it explosively rips water molecules
apart.
Dr. Christe said that the latest goal of his group was to synthesize an
all-nitrogen salt consisting of a positive ion of five nitrogen atoms bound to
a negative ion of five nitrogen atoms. Such a compound, containing 10
mutually linked nitrogen atoms, would be extremely difficult if not
impossible to synthesize, but it would probably pack stupendous chemical
energy that might be released with great explosive force.
Interesting links:
<a href="http://www.llnl.gov/str/June01/Manaa.html" target="_blank">http://www.llnl.gov/str/June01/Manaa.html</a>
<a href="http://www-cms.llnl.gov/buckyballs/research_proj.html" target="_blank">http://www-cms.llnl.gov/buckyballs/research_proj.html</a>