The element Hafnium (Hf) derives its name from the Latin for which capital city?

Hafnium is named after "Hafnia", the latin name for Copenhagen, where it was discovered. It is a chemical element with the chemical symbol Hf and atomic number of 72. It is a lustrous, silvery grey, ductile, tetravalent transition metal which chemically resembles zirconium .

Its existence was predicted in 1869 by Dmitri Ivanovich Mendeleev (1834 – 1907) who was a Russian chemist and inventor. The Hungarian Swedish chemist George Charles von Hevesy discovered hafnium in zircons by analyzing their X-ray spectra in 1923. A zircon is a mineral occurring as prismatic crystals, typically brown but sometimes in translucent forms of gem quality. It consists of zirconium silicate and is the chief ore of zirconium.

Hafnium is used in filaments and electrodes. Some semiconductor fabrication processes use its oxide for integrated circuits at 45 nm and smaller feature lengths. Some superalloys used for special applications contain hafnium in combination with niobium, titanium, or tungsten.

Hafnium's large neutron capture cross-section makes it a good material for neutron absorption in control rods in nuclear power plants, but at the same time requires that it be removed from the neutron-transparent corrosion-resistant zirconium alloys used in nuclear reactors.