Hafnium
Chemical element with atomic number 72 (Hf)
Hafnium is a chemical element; it has symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1922 by Dirk Coster and George de Hevesy. Hafnium...
