What are metalloids?


A metalloid is a chemical element that has properties intermediate between those of typical metals and non-metals . In general, chemical elements such as boron, silicon, germanium, arsenic, antimony and tellurium are considered under this classification. Rare elements like polonium and astate are also sometimes included. Most  metalloids are important industrial materials , used to make transistors and other semiconductor devices , ceramics, solar batteries, and certain polymers.


What are metalloids?

They are the elements of the periodic table that have intermediate properties between metals and non-metals and of which their main characteristic is that they are semiconductors rather than conductors .

  • Characteristics of metalloids
  • Properties
  • Uses and applications
  • Location of metalloids on the periodic table
  • Examples of metalloid elements

Characteristics of metalloids

The main characteristics of metalloids are the following:

  • They can be distinguished when their electrical conduction properties are studied .
  • They can be very varied in terms of shape and coloration .
  • They are located in the periodic table on a descending diagonal that goes from boron to astatine.
  • Some of them can be shiny and others opaque .
  • Some may have an allotropic state , which means that their presentation depends on the molecular structure.
  • Most of them are semiconductors , that is, they conduct electricity in only one direction and can be electrically insulated when faced with low temperatures.
  • They can also conduct heat energy in a better way.
  • Some of them represent a real danger to health, such as boron and arsenic, which can be lethal .
  • Some have a high atomic weight like polonium (127.60) or antimony (121.76), and others rather light like boron (10.81) and silicon (28.08).
  • Their densities can vary from 2.37 g / cm3 (boron) to 9.32 g / cm3 (polonium).
  • They have an electronic configuration in the last layer.
  • They have a poor ability to conduct heat.
  • They can form alloys of a metal with some other substance, giving it completely different characteristics.
  • They are capable of forming allotropes.


Like other elements, metalloids have a number of physical and chemical properties. Among the chemical properties we can mention that due to their enormous ionization potential and their intermediate electronic affinity , they have chemical properties that belong to metals and non-metals, so they are capable of reacting with both. The reactivity of metalloids will depend on the element with which it reacts .

The physical properties include a number of physical properties which also correspond to the metals and non metals. On the one hand they are solid and shiny at room temperature, but at the same time they are quite brittle and not malleable . They also have many intermediate properties of thermal and electrical conductivity allowing them to be used in various things. An interesting physical property is that metalloids contract when they melt .

It is also important to mention that metalloid oxides are amphoteric , this means that they have the ability to act as an acid or base in a reaction to produce a salt and water . The word “amphoteric” is a term that comes from the Greek word amphoteroi , which means ” both “, and this condition depends on the oxidation states that are available in a chemical. Because metals have intermediate oxidation states, they form amphoteric oxides .

Uses and applications

Being semiconductors, some have useful properties since they allow the flow of electricity through them, but in a controlled and controllable way. Semiconductors are basic due to their importance in electronics . Semiconductors, especially silicon, are used in the construction of radios , computers , televisions , telephones , and essentially every piece of machinery using computer chips .

Its resistance, lightness and insulation properties allow the construction of special glasses . Aerospace engineers manipulate boron glass for space capsules and other parts of space vehicles. A use that we all know is the production of Pyrex that are clear, strong and shock resistant, it is also used in test tubes , beakers, and shatterproof glass containers .

The insulating properties that metalloids possess make them used for protection against fire . Antimony is primarily used in a wide range of fireproof products. They use antimony to create car seats, clothing, and many other fire retardant products .

Location of metalloids on the periodic table

In the periodic table of the elements, metalloids are located on a diagonal line that goes from boron to astate . The elements on the upper right are non-metals, and those on the lower left are metals.

Examples of metalloid elements

Some examples of this important element are:

  • Boron (B)
  • Silicon (Si)
  • Germanium (Ge)
  • Arsenic (As)
  • Antimony (Sb)
  • Tellurium (Te)
  • Polonium (Po)

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