Definition

Hafnium is a chemical component with the symbol Hf and atomic number 72. A shiny, silvery gray, tetravalent conversion metal, hafnium chemically resembles zirconium and is found in zirconium minerals. Its survival was predicted by Dmitri Mendeleev in 1869. Hafnium was the second-to-last element of those with stable isotopes to be discovered. It was found by Dirk Coster and Georg von Hevesy in 1923 in Copenhagen, Denmark, and named Hafnia after the Latin name for "Copenhagen".

Properties

Hafnium is a shiny, silvery, ductile metal that is corrosion-resistant and chemically similar to zirconium. The physical properties of hafnium metal sample are noticeably affected by zirconium impurities, as these two elements are among the most difficult ones to separate because of their chemical similarity. A prominent physical difference between them is their density.

World Resources

Application

Hafnium is predictable to make up about 5.8 ppm of the Earth's upper crust by weight. It does not survive as a free element in nature, but is found combined in solid solution for zirconium in natural zirconium compounds such as zircon, ZrSiO4, which usually has a about 1 - 4 % of the Zr replaced by Hf.