Metalloid silicon, germanium, arsenic, antimony, and tellurium are commonly recognised as metalloids. Depending on the author, one or more from selenium, polonium, or astatine are sometimes added to the list. Boron sometimes is excluded, by itself, or with silicon. Sometimes tellurium is not regarded as a metalloid. The inclusion of antimony, polonium, and astatine as metalloids has been questioned. Other elements are occasionally classified as metalloids. These elements include hydrogen, beryllium, nitrogen, phosphorus, sulfur, zinc, gallium, tin, iodine, lead, bismuth, and radon. The term metalloid has also been used for elements that exhibit metallic lustre and electrical conductivity, and that are
Minor metals 40 percent of all production, but that China's share of global production increased 34 percent between 2000 and 2009. Minor metals are used in a wide diversity of end-use applications, from capacitors for consumer electronics (tantalum) and metallic cathodes for rechargeable batteries (cobalt) to photovoltaic solar cells (silicon) and semiconductor materials (gallium and indium).The primary end-uses of minor metals can also help to categorize the metals into four groups: Metals often classified as minor metals include: Antimony (Sb), Arsenic (As), Beryllium (Be), Bismuth (Bi), Cadmium (Cd), Cerium (Ce), Chromium (Cr), Cobalt (Co), Gadolinium (Gd), Gallium (Ga), Germanium (Ge), Hafnium (Hf),