Silicon metalloids

If you were to look at some ultra-pure, shiny-metallic crystalline silicon, you could be forgiven for thinking that it’s a metal. But appearances can be deceptive – it’s brittle at room temperature (a property of non-metals), and unlike metals it’s an intrinsic semiconductor (about which more below).

This mix of properties means that it is considered a metalloid, which is an imprecise term meaning neither a metal or a non-metal. The metalloids also include other elements in this part of the periodic table – namely boron, germanium, arsenic, antimony and tellurium, and sometimes a few others depending on exactly how you define the term.