As reported in the January 18, 2002 edition of Science
Science is the academic journal of the American Association for the Advancement of Science and is one of the world's top scientific journals....
at the Sapienza University of Rome, Fulvio Cacace and his colleagues created a new 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...
molecule known as tetranitrogen
, with the structure N4
. The structure, stability and properties of this molecule have been of great interest to research scientists in the last ten years.
Tetranitrogen is an unstable polynitrogen molecule with a lifetime of about a microsecond
A microsecond is an SI unit of time equal to one millionth of a second. Its symbol is µs.A microsecond is equal to 1000 nanoseconds or 1/1000 millisecond...
. At room temperature, it exists in the gas state. The structure consists of two closely bound N2
units connected by a longer weak bond. Due to its unstability, the N4
molecule readily disassociates into two more stable N2
molecules. This process is very exothermic
In thermodynamics, the term exothermic describes a process or reaction that releases energy from the system, usually in the form of heat, but also in the form of light , electricity , or sound...
, releasing ~800 kJ mol−1
Preparation and detection
Because tetranitrogen is so short-lived, preparing and detecting the molecule has been challenging to researchers. The approach that has proved most successful of producing a long-lived gaseous N4
species is the reduction of the gaseous N4+
molecule by neutralization-reionization (NR)-mass spectrometry
Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...
.The neutral N4
species had a lifetime in excess of the flight time from the neutralization to the reionization cell which is ~1μs.
Tetranitrogen may be useful in such applications as propellants and explosives due to its ability to release a large amount of energy when it breaks apart.
Hexazine is a hypothetical allotrope of nitrogen composed of 6 nitrogen atoms arranged in a ring-like structure analogous to that of benzene. It would be the final member of the azabenzene series, having all of the methylidyne groups of the benzene molecule replaced with nitrogen atoms...
(Nitrogen allotrope with formula N6)
Octaazacubane is a hypothetical allotrope of nitrogen, whose molecules have eight atoms arranged into a cube. It can be regarded as a derivative of cubane, where all eight carbon atoms have been replaced with a nitrogen atom...
(Nitrogen allotrope with formula N8)
The tetraoxygen molecule , also called oxozone, was first predicted in 1924 by Gilbert N. Lewis, who proposed it as an explanation for the failure of liquid oxygen to obey Curie's law...