Period 6 element the last stable element; all subsequent elements are radioactive. For bismuth, however, its only primordial isotope, Bi, has a half-life of more than 10 years, over a billion times longer than the current age of the universe. As a rule, period 6 elements fill their 6s shells first, then their 4f, 5d, and 6p shells, in that order; however, there are exceptions, such as gold. This period contains the lanthanides, also known as the "rare earths". Many lanthanides are known for their magnetic properties, such as neodymium. Many period 6 transition metals are very valuable, such as gold, however many
Hunan Nonferrous Metals Hunan Nonferrous Metals Hunan Nonferrous Metals Holding Group Co., Ltd. is a nonferrous metals company of China. It is a subsidiary of China Minmetals, which in turn indirectly under supervision of State-owned Assets Supervision and Administration Commission. Some of the assets of the conglomerate was listed in Hong Kong Stock Exchange from 2006 to 2015 as "Hunan Nonferrous Metals Corporation Limited" (SEHK: 2626). (The holding company retained Hunan Yaogangxian Mining Co., Ltd., Hunan Huangshaping Mining Branch and a joint venture (Duddar mine).) However, in 2014 China Minmetals announced the plan to privatization of the listed company, which China Minmetals already