The azide group (three nitrogens bonded together in a row, for the non-chemists in the crowd) has several personalities. Unfortunately, most of them are hostile. Azide anion, as you find in sodium azide, is pretty toxic. It shuts down several important enzymes, and it's often used in biology labs as a general metabolic poison.
Covalent azides are a different sort of beast. Having something directly bonded to the group stops it from being an enzyme-killer, for the most part, but you have a new problem to worry about: explosiveness. In general, reasonably high molecular weight azides are OK to handle (e.g., the early anti-HIV drug azidothymidine). I've made some of that sort, since azide displacement is a classic (and useful) way to get a nitrogen into your molecule. But the smaller ones aren't worth the risk.
That's because the higher the percentage of nitrogens in the formula, the more you have to worry. Thermodynamically, nitrogens bonded to each other are always regarded as guilty until proven innocent - there's always the fear that they're going to find a way to throw off their civilized clothes and revert to wild nitrogen gas. That's a hugely stable compound. If your structure goes that route, all that extra bonding energy it used to have ends up diverted into flying shrapnel and loud noises.
A few years ago I saw some Israeli escape artists has prepared triazidomethane, which I wouldn't touch with somebody else's ten-foot titanium pole. One carbon, one hydrogen, and nine nitrogens - look at the time! Gotta run! But there's always worse. Just today I was reading a soon-to-be-published paper in Angewandte Chemiefrom some daredevils at USC. They've prepared titanium tetraazide, of all things. One titanium and twelve nitrogens: whoa! Podiatrist appointment! See you later!
You can isolate the stuff, it seems, as long as you handle it properly. It turns out that brutal treatments like, say, touching it with a spatula, or cooling down a vial of it in liquid nitrogen - you know, rough handling - make it detonate violently. I think that staring hard at it is OK, though. The authors recommend using everything you have for protection if you're zany enough to follow their lead: goggles, blast shield, face shield, leather suit (!) and ear plugs. Those last two suggestions are unique in my experience, and quite. . .evocative of what you have to look foward to with these compounds. (We don't have any leather suits around where I work, although I'm sure I'd look dashing in one.)
Some of the folks on the paper have a joint appointment with an Air Force missile propulsion research lab. They've found a home. Me, I'll be way over here.