Metalloids: Definition, Examples and Uses Explained

Chemistry becomes more interesting when we explore elements that do not completely fit into one category. Metalloids are a perfect example of this uniqueness. Importantly, they are elements that show properties of both metals and non-metals, making them special and scientifically important. 

This article covers what metalloids are, where they are located in the periodic table, their physical and chemical properties and their real-life applications.

Table of Contents 

• What are Metalloids
• General Properties of Metalloids
• Applications of Metalloids
• Metalloids Benefits with Toxic Effects

What are Metalloids

Metalloids are chemical elements whose physical and chemical properties lie between metals and non-metals. They show a mix of metallic and non-metallic characteristics. Many periodic tables highlight this boundary to separate metals and non-metals and metalloids are found along this dividing region.

But why is it important to understand Metalloids 

Understanding metalloids helps students:

• Differentiate clearly between metals and non-metals.
• Understand semiconductor technology.
• Connect chemistry concepts with real-life applications like mobile phones and computers.

The seven most widely recognised examples of metalloids are:

• Boron
• Silicon
• Germanium
• Arsenic
• Antimony
• Tellurium
• Polonium

These examples of metalloids are located in a diagonal zig-zag line in the p-block of the periodic table, extending from boron (upper left) to astatine (lower right). 

These elements are located in a diagonal zig-zag line in the p-block of the periodic table, extending from boron (upper left) to astatine (Lower right).

When it comes to the Position of Metalloids in the Periodic Table Metalloids are placed between metals (on the left side) and non-metals (on the right side). Their position itself explains why their properties are intermediate.They are mostly found in groups 13 to 16 of the periodic table and belong to the p-block elements.

Read More: 118 elements their symbols atomic numbers

General Properties of Metalloids

1. Physical Properties

• They usually appear shiny like metals.
• They are brittle, meaning they break easily when hammered.
• Most metalloids are solids at room temperature.
• They have moderate electrical conductivity, making them semiconductors.
• They are neither very good conductors like metals nor poor conductors like non-metals.

Because of these characteristics, metalloids are widely used in the electronics industry.

2. Chemical Properties 

• Chemically, metalloids generally behave more like non-metals.
• They form covalent compounds.
• Their oxides are usually amphoteric or weakly acidic.
• They have intermediate electronegativity and ionisation energy.
• They can form alloys with metals.

Example of oxide formation:

Si+O2→SiO2

Here, silicon forms silicon dioxide, which behaves as a weakly acidic oxide.

Do you know? Metalloids often behave as semiconductors because of their band structure. 

For example Electronic configuration of Silicon:

1s2 2s2 2p6 3s2 3p2

Valence electrons can also be written as:

Si:3s23p2

This explains why silicon can form four covalent bonds.

Applications of Metalloids

Metalloids play a major role in modern technology and industry.

1.In Electronics and Semiconductors; Silicon and germanium are widely used in semiconductor devices. They are used in microchips, transistors, solar cells and computer components.

2.In Alloys, Boron is used in steel to increase hardness. Ferroboron (about 15% boron) is added to steel for strengthening. Nickel-boron alloys are used in welding and engineering industries.

3.In Glass and Ceramics; Silicon dioxide is used in glass manufacturing. And Borosilicate glass is heat-resistant and used in laboratories.

4. In Flame Retardants and Pyrotechnics, antimony compounds are used as flame retardants. Metalloids are also used in fireworks and pyrotechnic mixtures.

5. In Optoelectronics, optical storageis used in LED technology, fibre optics and storage devices.

Metalloids Benefits with Toxic Effects 

Metalloids have both beneficial and toxic effects depending on their form and concentration.

• Boron is an essential trace element and has antiseptic properties (boric acid).
• Arsenic compounds have been used in certain medicines, though they are toxic in high doses.
• Silicon is important for bone health.
• Antimony compounds are used in treating parasitic diseases.
• Germanium and tellurium are being researched for potential medical uses.

However, some metalloids like arsenic and polonium can be highly toxic and must be handled carefully.

So far, we have come to know that Metalloids are unique elements that beautifully bridge the gap between metals and non-metals. They combine the shine of metals with the chemical behaviour of non-metals, making them scientifically special and technologically valuable. From semiconductors and solar panels to medicines and alloys, their applications are vast and impactful.