WATER
Water,
common name applied to the liquid state of the hydrogen-oxygen
compound H2O. The ancient philosophers regarded water as a basic
element typifying all liquid substances.
Scientists did not
discard that view until the latter half of the 18th century. In
1781 the British chemist Henry Cavendish synthesized water by
detonating a mixture of hydrogen and air. However, the results of
his experiments were not clearly interpreted until two years
later, when the French chemist Antoine Laurent Lavoisier proposed
that water was not an element but a compound of oxygen and
hydrogen. In a scientific paper presented in 1804, the French
chemist Joseph Louis Gay-Lussac and the German naturalist
Alexander von Humboldt demonstrated jointly that water consisted
of two volumes of hydrogen to one of oxygen, as expressed by the
present-day formula H2O. Almost all the hydrogen in water has an
atomic weight of 1. The American chemist Harold Clayton Urey
discovered in 1932 the presence in water of a small amount (1 part
in 6,000) of so-called heavy water, or deuterium oxide (D2O);
deuterium is the hydrogen isotope with an atomic weight of 2. In
1951 the American chemist Aristid Grosse discovered that naturally
occurring water contains also minute traces of tritium oxide
(T2O); tritium is the hydrogen isotope with an atomic weight of 3.