Metalloid: definition in chemistry
Metalloid: An element with properties in between those of metals and nonmetals. Boron, silicon, germanium, arsenic, antimony and tellurium are usually counted as metalloids.
Metalloids often look shiny like metals but are brittle like nonmetals, and they conduct electricity only moderately. Several, especially silicon and germanium, are semiconductors whose conductivity can be finely controlled by adding tiny amounts of other elements, which makes them the basis of computer chips and solar cells. Their chemistry is mixed too: their oxides tend to be weakly acidic or amphoteric.
Examples
- Silicon — the main material of computer chips
- Boron — added to glass to make heat-resistant borosilicate glassware
- Germanium — used in early transistors and in fiber optics
- Arsenic — combined with gallium in LEDs and laser diodes
On the periodic table
Metalloids lie along the zigzag staircase line that runs from boron down toward astatine, separating the metals on the left from the nonmetals on the right.