Metalloid for carbon in steel casting. Of the non-metallic elements less often recognised as metalloids, selenium—in the form of ferroselenium (50–58% selenium)—is used to improve the machinability of stainless steels. All six of the elements commonly recognised as metalloids have toxic, dietary or medicinal properties. Arsenic and antimony compounds are especially toxic; boron, silicon, and possibly arsenic, are essential trace elements. Boron, silicon, arsenic, and antimony have medical applications, and germanium and tellurium are thought to have potential. Boron is used in insecticides and herbicides. It is an essential trace element. As boric acid, it has antiseptic, antifungal, and antiviral properties.
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),