Background | Name | Sources | Uses | Substitutes and Alternative Sources
Background Hafnium is a bright silver, ductile, lustrous metallic element with a very high melting point. Its atomic number is 72 and its symbol is Hf. Hafnium is the 45th most abundant element in the Earth’s crust with an average crustal abundance of 3 ppm (parts per million). The element was discovered by Dirk Coster and George Charles von Hevesey by separating it from zirconium in 1923.
Hafnium does not react with air, water, acids or bases. It is similar to the element cadmium in that it absorbs neutrons. This feature makes hafnium useful as a control rod material in nuclear reactors.
There is no biological use or benefit for hafnium. It is present in ocean water in very small amounts, specifically 0.008 ppb by weight (parts per billion). For comparison, hafnium is far more concentrated in the Earth’s crust at 3,300 ppb by weight.
