Re: Do nitrogen ions exist?

Hello Allan.

Most of the time, chemists play around with water and simple organic solvents and 
a variety of solids. Nitrogen ions generally (but wait till a little later in my 
answer) and N(3+) in particular are not usually found in these situations. But 
there are lots of other very different sorts of environment that are 'natural'.

A nitrogen atom holds onto its electrons very tightly. It takes quite a bit of 
energy to remove them. A nitrogen atom also has almost no affinity for extra 
electrons to make a negative ion. But in a natural high energy environment like 
the atmosphere of the sun, or in an artificial situation like a carbon arc, you 
can find spectroscopic evidence for N(+) N(2+) and N(3+) at least.

One of the most important things about the chemistry of nitrogen is that a 
nitrogen atom holds onto another nitrogen atom very strongly. The triple bond in 
nitrogen gas is almost the strongest chemical bond known, which means that 
nitrogen gas is a very stable and unreactive material. It is the only molecule I 
know (there may be one or two others, but not many) whose molecule cannot be 
split into atoms by ultraviolet light. What a nitrogen molecule does when it 
absorbs short wavelength UV light is not to split into two nitrogen atoms, but 
instead to lose an electron to form a nitrogen molecular ion N2(+). N2(+) is 
naturally present in the earth's atmosphere in significant amounts above about 
150 km altitude.

And now that we have got to talking about molecular ions, I can mention the one 
and only nitrogen ion that is moderately stable in solutions and normal chemical 
sorts of situations. That is the azide ion, N3(-), which can be found in salts 
like sodium azide, Na(+)N3(-), or as a solvated ion in water. I say only 
'moderately' stable, because azides are explosive, and often a bit too delicate 
for safe handling.

Reference information can be found in the CRC Handbook of Physics and Chemistry
(spectroscopic info about N+, N(2+) and N(3+) and physical and chemical 
properties of sodium azide), and R.P. Wayne 'Chemistry of Atmospheres' (N+ and 
N2(+) in the upper atmosphere, interaction of nitrogen gas with UV light).