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What
the name means:
Iodine is named after the Greek word
ioeides, meaning “violet coloured”.
Who
identified
iodine? Bernard
Courtois was a Frenchman who had been
trained as a pharmacist. His father owned a
factory that made saltpeter or niter.
Saltpeter is a name given to potassium
nitrate and sodium nitrate. There was a big
demand for saltpeter at that time since it
was an essential ingredient of gunpowder.
In
order to make the saltpeter seaweed was
collected from the Normandy and Brittany
coastlines. This seaweed was then burned
and the ashes were taken to the factory.
Here they were treated with sulphuric acid
as part of the process to obtain the
saltpeter.
In
1811, Bernard Courtois made a mistake and
added too much sulphuric acid to the ashes.
The result was the production of a
violet-coloured gas. Courtois collected
some of this gas and, on cooling, it
produced dark crystals. He was convinced
that he had discovered something new but,
since he didn’t have enough money to
continue his research, he passed samples of
his crystals to various French chemists.
Charles Bernard Desomes and Nicolas Clement
took up the research and presented their
findings to the Institute of France in
1812. Louis-Joseph Gay-Lussac and Humphry
Davy also received a sample from Courtois.
Davy recognised that the new element had
similar properties to chlorine and
fluorine. He named the new element iodine.
After an argument about who had been the
first to identify iodine, the chemists
involved accepted that Bernard Courtois
should take the credit.
About
iodine: Iodine,
in the form of iodide salts, is found in
sea water and salt deposits. Iodine gas has
a pungent odour and is purple-violet in
colour. It dissolves in water to form a
dark brown solution that is used as an
antiseptic. Iodine is used to make some
dyes and inks. It is an essential element
for humans since it is needed for the
thyroid gland in the neck to function
properly. |
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