Semimetals or metalloids: characteristics and examples

On the periodic table, these elements are located in a zigzag pattern, between metals and nonmetals.

Characteristics and properties of metalloids

Metalloids differ from metals and nonmetals because they have certain particular characteristics. In some cases, they have physical properties similar to those of metals. In other cases, based on their chemical properties, they are more similar to nonmetals.

The most important characteristics of metalloids are:

• Appearance : they can be shiny or opaque.
• Conductivity : they are semiconductors, especially silicon and germanium. The other elements are not semiconductors by themselves, but they can be if they are combined with other elements. Furthermore, metalloids are better thermal conductors than nonmetals.
• Malleability : they are malleable, which allows their use in different fields of industry.
• Number of electrons: In their last orbit, they have three valence electrons or more. During chemical reactions they can gain or lose electrons. 
• Flexibility : having intermediate characteristics, metalloids can react in different ways, depending on their exposure to a metal. In that case they will tend to react as a non-metal. Conversely, if they are exposed to a non-metal, they are likely to react like a metal.
• Toxicity : they are usually toxic or harmful to health. Some of them are essential for living beings, but in certain quantities they can be lethal. This is the case of arsenic or boron. Polonium, meanwhile, is highly radioactive.

Applications and uses

The characteristics of semimetals give them great utility. Currently they are used in different applications. These include the manufacture of:

• Electronic devices.
• Rectifiers.
• transistors.
• Diodes.
• Integrated circuits.
• Chips and microprocessors.
• pesticides.
• Sealing materials.
• Catalysts.
• Optical fibers.
• Alloys.
• Glass.
• Enamels.
• Medicines.

Bibliography

• Pérez Agustí, A. Metal poisoning: Heavy metals, non-metals, metalloids and others . (2019). Spain. B07MQGJVK6.
• Zikrillayev, N.; Saitov, E. Silicon Materials: The Future of Photovoltaics. (2020). Spain. Spanish Academic Editorial.
• García Bello, D. Everything is a matter of chemistry. (2016). Spain. Paidos.