What does semimetal mean?
A semimetal is a chemical element whose characteristics fall between those of metals and nonmetals. Semimetals commonly have a metallic appearance and conduct electricity better than nonmetals, but they are generally brittle and are not readily shaped or drawn like ordinary metals. Silicon, boron, germanium, arsenic, antimony, and tellurium are often classified as semimetals. The term is particularly relevant to electronics: silicon, for example, is a semimetal used extensively in semiconductors, computer chips, solar cells, and optical fibres. In contemporary scientific usage, “metalloid” is often preferred and may simply replace “semimetal.” Neither term implies that an element is literally half a metal; rather, it describes an intermediate or mixed set of physical and chemical properties. The boundaries are not absolute, and individual elements may differ in their behaviour depending on the conditions in which they occur.
nounA chemical element whose properties are intermediate between those of metals and nonmetals, such as silicon, boron, or arsenic. The term is often used interchangeably with “metalloid.”
- An element, such as boron, silicon, or arsenic, having properties intermediate between those of metals and nonmetals.
"Silicon is a semimetal widely used in semiconductors and solar cells."
"Arsenic is classified as a semimetal and is toxic in many of its chemical forms."
"The material was chosen for its semimetal properties and high electrical conductivity."
The plural is used when referring to several elements classified as semimetals.
"Boron and silicon are semimetals with important industrial uses."
Some elements straddle the divide between metal and nonmetal—making “semimetal” a chemical category with no neat line in the periodic table.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does semimetal come from?
Semimetal was formed in English by combining the prefix “semi-” with “metal.” Both elements come from Greek roots: “semi-” derives from Greek sēmi, meaning “half,” while “metal” derives through Latin from Greek metallon, meaning “mine” or “metal ore.” Related English words include “metallic,” “metallurgy,” and “metalloid.”
Related word forms
How semimetal is actually used
The term is chiefly technical and is less common in modern scientific writing than “metalloid.” Classification can vary because the boundary between metals and nonmetals is not absolute.
Easily confused with semimetal
Metalloid is the more common modern term for an element with properties between those of metals and nonmetals and is often used synonymously with semimetal.