Chlorine is a greenish-yellow, nonflammable
gas with a distinctive, pungent odor. It is almost
two and one-half times as heavy as air. The gas
acts as a severe irritant if inhaled. Chlorine liquid
has the color of clear amber and is about
one and one-half times as heavy as water. It is
shipped as a compressed liquefied gas having a
vapor pressure of 86.767 psig at 70°F (598.26
kPa at 21.1°C). Chlorine is nonflammable in
both gaseous and liquid states. However, like
oxygen, it is capable of supporting the combustion
of certain substances. Many organic chemicals
react readily with chlorine, in some cases
with explosive violence. Chlorine usually forms
univalent compounds, but it can combine with a
valence of 3, 4,5, or 7.
Chlorine is only slightly soluble in water.
When it reacts with pure water, weak solutions
of hydrochloric and hypochlorous acids are
formed. Chlorine hydrate (Cl2·8H20) may crystallize
below 49.3°F (9.61°C).
