My thoughts are

1. Don't they teach English grammar in schools these days?

2. Even if NF gas (never heard of it myself, but I'll take your word for it)
is not *thermodynamically* stable with respect to N and F atoms,
this does not necessarily mean it will decompose under "normal" conditions, as it might be *kinetically* stable.

It's hard to predict these thermodynamic and (particularly) kinetic properties by calculation from theory (although of course the periodic table can help guide you as to comparative trends) ... only real way is to find out empirically (or look it up ;-)

Nor have I. This site doesn't mention a compound NF.
"Fluorides
N2F2
N2F2
NF3
N2F4 "

I have done,but cannot find much anywhere - hence the post here looking for help.

So if NF(g) existed,it wouldn`t be stable under normal conditions.
Is NF(g) stable in respect of N and F atoms???

Didn't you read what I just typed???

I don't think your compound actually exists anyways,
unless it was some transient radical species.

To find out its hypothetical thermodynamic stability,
you need to look up the relevant thermodynamic
properties and make a nice little born-haber diagram
(or whatever it is they're called)

But even this won't give you the answer cos you'd
need to know about the kinetics as well.

I get 286 references for Nitrogen Flouride(NF) on scifinder scholar. Go to your local university library and they can probably help you out further

thank`s,I`ve just been using google so far.