#Last edited on 2013-02-06 06:16:31 by stolfilocal

----------------------------------------------------------------------
# Old head
{{redirect|Free radical}}
[[Image:Gombergm01.jpg|right|thumb|[[Moses Gomberg]] (1866-1947), the founder of radical chemistry]]
'''Radicals''' (often referred to as '''free radicals''') are [[atom]]s, [[molecule]]s, or [[ion]]s with [[unpaired electron]]s or an [[open shell]].  With some exceptions, these unpaired electrons cause radicals to be highly [[chemical reaction|chemically reactive]].

Free radicals play an important role in [[combustion]], [[atmospheric chemistry]], [[polymerization]], [[Plasma (physics)|plasma]] chemistry, [[biochemistry]], and many other chemical processes. In living organisms, [[superoxide]] and [[nitric oxide]] and their reaction products regulate many processes, such as control of vascular tone and thus blood pressure.  They also play a key role in the intermediary metabolism of various biological compounds. Such radicals can even be messengers in a process dubbed [[redox signaling]].  A radical may be trapped within a ''[[Cage effect (chemistry)|solvent cage]]'' or be otherwise bound.