Zirconium oxide was discovered in 1789 by the German chemist, Martin Heinrich Klaproth, and the metal itself was first isolated by J÷ns Jacob Berzelius in 1824. Klaproth also discovered the oxide of titanium, but had been beaten to this by William Gregor, who found the oxide in 1791, four years before the German. Berzelius, again, was involved in isolating an impure sample of the metal in 1825.
Hafnium was discovered in 1923 by the Dutch scientist, Dirk Coster, and the Hungarian scientist, Georg von Hevesy, after an earlier claim for the discovery of element 72, by Georges Urbain, had been discredited.
