Hexanitrogen ( diazide, hexaaza-1,2,4,5-tetraene) is an allotrope of nitrogen with the formula N6. The six nitrogen are all covalent bond in a single molecule: two azide units linked to each other. Its stability and structure were theorized in 2016
Its synthesis has been regarded as highly significant, as higher allotropes of nitrogen have potential application as , or energy storage.
Synthesis
It is synthesized by the reaction of
silver azide (AgN
3) with
chlorine or
bromine gas under reduced pressure at room temperature via
chlorine azide or
bromine azide as the intermediate. The product is collected by
matrix isolation in solid
argon (10
Kelvin) or by condensation on a
liquid nitrogen cooled surface (77 K).
Structure
All six atoms form a single chain, resembling two
azide (N
3) units linked together.
Computational analysis predicts that the
in the molecule vary significantly, indicating a complex electronic distribution, and a
trans geometry in the central part of the structure. The terminal double bonds (N1=N2 and N5=N6) are about 1.138 Å. The adjacent double bonds (N2=N3 and N4=N5) are slightly longer, about 1.251 Å, and the central single bond (N3–N4) is the longest, about 1.460 Å. Each azide-like unit is approximately linear, with
of about 172.5° at N2 and N5, and distinctly bent geometry of about 107° at N3 and N4.
Decanitrogen
A world-renowned chemist Sir
Martin Poliakoff proposed his idea of a 10 nitrogen atom allotrope after learning about hexanitrogen. The concept is based on the fact that azide anion is a
pseudohalogen. Considering that trihalogenic nitrogen compounds (like nitrogen trichloride) exist, Poliakoff suggests that nitrogen triazide (
N(N) or
N) may also be stable under certain conditions.
See also
