This is part of a series of caches all using the same container. The experiment continues... these containers generally hold up very well unless the lid is not secured well, please make sure you close the container tightly.
************** HAFNIUM ***************
Atomic Number: 72
Symbol: Hf
Atomic Weight: 178.49
Discovery: Dirk Coster and Georg von Hevesy 1923 (Denmark)
Name Origin: Hafnia, the Latin name of Copenhagen.
Properties: A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869. Hafnium was the penultimate stable isotope element to be discovered (rhenium was identified two years later). Hafnium is named after Hafnia, the Latin name for "Copenhagen", where it was discovered.
Uses: 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.
Sources: Hafnium is estimated to make up about 5.8 ppm of the Earth's upper crust by weight. It does not exist 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 about 1 – 4% of the Zr replaced by Hf. A major source of zircon (and hence hafnium) ores are heavy mineral sands ore deposits, pegmatites particularly in Brazil and Malawi, and carbonatite intrusions particularly the Crown Polymetallic Deposit at Mount Weld, Western Australia. A potential source of hafnium is trachyte tuffs containing rare zircon-hafnium silicates eudialyte or armstrongite, at Dubbo in New South Wales, Australia. Hafnium reserves are projected to last under 10 years if the world population increases and demand grows.
Information Sources - http://en.wikipedia.org/wiki/Hafnium
http://chemistry.about.com/library/blperiodictable.htm