Nitrogen makes up the major portion of the atmosphere
(78.08 percent by volume, 75.5 percent
by weight). It is a colorless, odorless,
tasteless, nontoxic, almost totally inert gas, and
is colorless as a liquid. Nitrogen is nonflammable,
will not support combustion, and is not life
supporting. It combines with some of the more
active metals such as lithium and magnesium to
form nitrides, and at high temperatures it will
also combine with hydrogen, oxygen, and other
elements. It is used as an inert protection against
atmospheric contamination in many nonwelding
applications. Nitrogen is only slightly soluble in
water and most other liquids, and is a poor conductor
of heat and electricity. As a liquid at
cryogenic temperatures it is nonmagnetic. It is
shipped as a nonliquefied gas at pressures of
2000 psig (13 790 kPa) or above, and also as a
cryogenic fluid at pressures and temperatures
below 200 psig (1380 kPa) and -261°F
(-163°C).
