A CENTURY OF PROGRESS 125
by the number and kinds of atoms
in the molecule but also by the
atoms’ arrangement. The same
formula may apply to different
structures with different
properties—these different
structures were later named
isomers by Berzelius.
Wöhler and Liebig went on to
forge a brilliant partnership, but it
was Wöhler alone who, in 1828,
stumbled upon the truth about
organic chemicals.
The Wöhler synthesis
Wöhler was mixing silver cyanate
with ammonium chloride, expecting
to get ammonium cyanate. Instead,
he got a white substance that had
different properties from ammonium
cyanate. The same powder appeared
when he mixed lead cyanate with
ammonium hydroxide. Analysis
showed the white powder to be
urea—an organic substance that is
a key component of urine, and has
the same chemical formula as
ammonium cyanate. According to
Berzelius’s theory, it could be made
only by living things—yet Wöhler
had synthesized it from inorganic
chemicals. Wöhler wrote to Berzelius:
“I must tell you that I can make
urea without the use of kidneys,”
explaining that urea was in fact an
isomer of ammonium cyanate.
The significance of Wöhler’s
discovery took many years to sink
in. Even so, it paved the way for the
development of modern organic
chemistry, which not only reveals
how all living things depend on
chemical processes, but enables
the artificial synthesis of valuable
organic chemicals on a commercial
scale. In 1907, a synthetic polymer
called Bakelite was produced from
two such chemicals and ushered in
the “Age of Plastics” that shaped
the modern world. ■See also: Antoine Lavoisier 84 ■ John Dalton 112–13 ■
Jöns Jakob Berzelius 119 ■ Leo Baekeland 140–41 ■ August Kekulé 160–65
Friedrich Wöhler
Born in Eschersheim, near
Frankfurt in Germany,
Friedrich Wöhler trained in
obstetrics at the University
of Heidelberg. But chemistry
was his passion and, in 1823,
he went to study with Jöns
Jakob Berzelius in Stockholm.
On his return to Germany, he
embarked on a remarkable
and varied career in chemical
research and innovation.
Besides the first artificial
synthesis of an organic
substance, Wöhler’s many
discoveries—often made with
Justus von Liebig—included
aluminum, beryllium, yttrium,
titanium, and silicon. He also
helped to develop the idea of
“radicals”—basic molecular
groups from which other
substances are built. Although
later disproved, this theory
paved the way for today’s
understanding of how
molecules assemble. In later
years, Wöhler became an
authority on the chemistry of
meteorites and helped set up
a factory for purifying nickel.Key works1830 Summary of
Inorganic Chemistry
1840 Summary of
Organic ChemistryYet by mixing two
ordinary chemicals in the
lab, we can produce
urea—the organic
chemical in urine.We can make
organic substances
from inorganic
substances.Organic substances
are not unique.Some chemists think that
organic chemicals found
in living things are unique
and can only be made
by living things.