It is pure nitrogen in a liquid state at a very low temperature.

We must keep our masks on despite the air, which is pure nitrogen.

Someone that breathes in pure nitrogen will just fall asleep and die.

He knew; that wasn't air in the air lines; it was pure nitrogen or helium or something.

When used as a cryocooler it is preferable to use gas mixtures instead of pure nitrogen.

Inhaling the pure nitrogen, patients lose consciousness immediately (in approximately 12 seconds) and die a few minutes later.

But in residence, oxygen supply was cut to zero, leaving pure nitrogen, and left that way ten minutes.

It can also be used in the preparation of extra pure nitrogen on heating:

This problem can be solved by purging the vacuum system with dry pure nitrogen before pump down.

The catalyst can't find any pure nitrogen to work on.