Element Hafnium, Hf, Transition Metal

In 1911 Urbain noticed several new lines in spectrum of the fractions of yttria mother solution and, thinking he had found a new element similar to the rare earths, called it celtium. After Moseley's discovery of elements x-ray spectra and of atomic numbers, it was found that the new element's number should be 72. However Moseley had not detected the lines of the element #72 in Urbain's celtium. He asked the physicist Alexandre Dauvillier to retry the experiment. Dauvillier identified two faint lines specific to the element 72, the same as in celtium, thus claiming to have spectroscopic evidence to support the discovery and the name. However, the atomic theory, developed by Niels Bohr had riddled such claim. Bohr was confident that the element 72 would have been a member of group 4 and was more likely to be found along with zirconium than with the rare earths. Dirk Coster and Hungarian scientist Gyorgy Karl von Hevesy, which had been working in Bohr's laboratory in Copenhagen, used X-ray spectroscopic analysis to show that element 72 was present in Norwegian zircon. Subsequently, it was named hafnium, ancient Hafnia for Copenhagen, Kobenhavn in Danish, the Niels Bohr's town.

Transition metal Hafnium is an element with an average crustal abundance of (3-4)x10^-4 mass %. Hafnium minerals are not commonly known, in the Earth crust it is associated with zirconium. Hafnium is a trace element dispersed as an isomorphic impurity in zirconium minerals, 1-2% from mass of (ZrO₂ + HfO₂). In some sorts of zircon Hafnium concentration is even higher, 31% in hafnium zircon, up to 24% in cytrolite, 15% in alvite, and 10% in naegite. Thortveitite (Y, Sc)Si₂O₇ contains zirconium and hafnium as impurities, with hafnium predomination.