Manganese than one minute. The primary decay mode before the most abundant stable isotope, Mn, is electron capture and the primary mode after is beta decay. Manganese also has three meta states. Manganese is part of the iron group of elements, which are thought to be synthesized in large stars shortly before the supernova explosion. Mn decays to Cr with a half-life of 3.7 million years. Because of its relatively short half-life, Mn is relatively rare, produced by cosmic rays impact on iron. Manganese isotopic contents are typically combined with chromium isotopic contents and have found application in isotope geology and
Manganese still known as Hadfield steel (mangalloy). It was used for British military steel helmets and later by the U.S. military. The second largest application for manganese is in aluminium alloys. Aluminium with roughly 1.5% manganese has increased resistance to corrosion through grains that absorb impurities which would lead to galvanic corrosion. The corrosion-resistant aluminium alloys 3004 and 3104 (0.8 to 1.5% manganese) are used for most beverage cans. Before 2000, more than 1.6 million tonnes of those alloys were used; at 1% manganese, this consumed 16,000 tonnes of manganese. Methylcyclopentadienyl manganese tricarbonyl is used as an additive in unleaded gasoline