Metalloids Explained: Key Differences, Properties, and Real-World Applications

Have you ever wondered about the special elements that make your smartphone work or help solar panels collect energy from the sun? Those are likely metalloids – a unique group of elements that sit between metals and non-metals on the periodic table. In this article, we’ll explore what makes metalloids special, how they differ from each other, and why they matter in our everyday lives.

What Are Metalloids?

Metalloids are elements that show both metal and non-metal traits. Think of them as the “in-between” elements. They sit along a diagonal line in the periodic table between the metals on the left and non-metals on the right.

These special elements share some key features:

• They can partly conduct electricity (not as well as metals, but better than non-metals)
• They are brittle solids at room temperature
• Their electronegativity typically ranges from 1.8 to 2.2
• They can form alloys with metals

There are 7 common metalloids:

1. Boron (B)
2. Silicon (Si)
3. Germanium (Ge)
4. Arsenic (As)
5. Antimony (Sb)
6. Tellurium (Te)
7. Polonium (Po)

Metalloid Comparison: Properties and Uses

Let’s look at each metalloid and what makes it unique and useful.

Boron

Boron is a lightweight but tough metalloid with a very high melting point of 2,076°C. It’s not found free in nature but is often combined with oxygen in compounds like borax.

Key Uses:

• Flame retardants for fabrics and materials
• Borosilicate glass (like Pyrex) that can handle high heat
• Neutron shields in nuclear reactors
• Medicine as antiseptics and supplements

The global boron market is worth about $2.1 billion, with 80% used in glass and ceramics production.

Silicon

Silicon is the second most abundant element in Earth’s crust, making up about 27.7% of its weight. It’s the most common metalloid and extremely important in modern technology.

Key Uses:

• Computer chips and electronic devices
• Solar panels that convert sunlight to electricity
• Silicone products like sealants and medical implants
• Glass production

Silicon dominates 95% of the semiconductor market, making it one of the most important elements in our tech-driven world.

Germanium

Germanium is special because it’s transparent to infrared light while still being a semiconductor. Though not common in Earth’s crust, it has unique optical properties.

Key Uses:

• Fiber optic cables that carry internet data
• Infrared optics for night vision devices
• Transistors and other electronic components

About 35% of germanium is used in fiber optics, with the market expected to reach $390 million by 2027.

Arsenic

Arsenic is known for being toxic, but it has important uses when handled safely. It forms brittle alloys and has been used throughout history.

Key Uses:

• Semiconductors (especially in gallium arsenide chips)
• Wood preservatives (though this use has declined)
• Metal alloys to increase hardness

The global arsenic market has decreased by about 70% since 2000 due to toxicity concerns and bans on certain uses.

Antimony

Antimony makes alloys harder and more resistant to corrosion. It has been known since ancient times and has a silvery appearance.

Key Uses:

• Flame retardants for textiles and plastics
• Lead-acid batteries for cars
• Pewter and other metal alloys

About 60% of antimony is used in flame retardants, and it’s becoming important in some lithium-ion battery anodes.

Tellurium

Tellurium is photoconductive – it conducts electricity better when exposed to light. It’s rare but valuable for specialized applications.

Key Uses:

• Solar panels (cadmium telluride or CdTe panels)
• Thermoelectric devices that convert heat to electricity
• Metal alloys to improve machinability

Tellurium helps boost solar panel efficiency to about 22% in CdTe panels. About 40% of the global supply comes from copper refining.

Polonium

Polonium is radioactive and extremely rare. It was discovered by Marie Curie in 1898. Due to its radioactivity (it’s about 250,000 times more radioactive than uranium), it has very restricted uses.

Key Uses:

• Static eliminators in specialized industrial settings
• Nuclear batteries for space applications
• Research purposes

Polonium-210 has a half-life of just 138 days, and it was historically used in Soviet lunar rovers for heating during the cold lunar nights.

Key Differences at a Glance

The table below shows how these metalloids compare in key properties:

Top Industrial & Everyday Applications

The global market value of metalloids shows their importance in industry:

Electronics

Silicon is the king of electronics. More than 95% of all electronic devices use silicon semiconductors in their chips and circuits. From your smartphone to your car’s computer, silicon makes it possible. Germanium is used in specialized transistors and other electronic components.

Energy

Tellurium is crucial for certain types of solar panels. CdTe solar panels produce 75% less carbon emissions than traditional silicon panels. Meanwhile, boron is used in nuclear reactors as a neutron shield, helping to control reactions safely.

Materials

Antimony is added to many materials as a flame retardant. When your furniture or children’s clothing is labeled “flame resistant,” it might contain antimony compounds. Silicon is also used to create silicone polymers found in everything from kitchen utensils to medical implants.

Medicine

Boron compounds are used in antiseptics and treatments for arthritis. Historically, arsenic was used in medicines, though its use today is very limited due to toxicity concerns.

Safety and Environmental Considerations

While metalloids enable modern technology, some present serious safety concerns:

Arsenic is particularly concerning, with over 20,000 deaths annually from arsenic-contaminated groundwater, primarily in Bangladesh and parts of India.

Polonium is extremely dangerous – just one microgram is a lethal dose for humans. It gained public attention in 2006 when it was used to poison the former Russian spy Alexander Litvinenko.

Many countries have strict regulations about the use of these elements in consumer products. For example, arsenic has been banned from most wood preservatives in residential settings in the United States since 2003.

Real-World Case Studies

Case Study 1: Silicon in Apple’s M1 Chip

Silicon’s semiconductor properties have revolutionized computing. Apple’s M1 chip uses 5-nanometer process technology to pack 16 billion transistors onto a tiny chip. This advanced silicon doping (adding small amounts of other elements) reduces power use by 60% while doubling speed compared to previous generations.

Case Study 2: Tellurium in First Solar’s Panels

First Solar controls about 50% of the thin-film solar market with its CdTe panels. These panels use tellurium to achieve efficiency ratings of 22%, making solar power more affordable. The company’s panels have a smaller carbon footprint than traditional silicon panels.

Case Study 3: Boron in Nuclear Safety

Boron carbide is used in control rods in 100% of commercial nuclear plants globally. Its ability to absorb neutrons makes it essential for preventing meltdowns in emergency situations. During the Fukushima disaster in 2011, boron was dumped into reactors to help stop nuclear chain reactions.

Future Trends in Metalloid Use

The future looks bright for metalloids in several cutting-edge fields:

Quantum Computing

Both silicon and germanium are being researched for use in quantum bits or “qubits.” Silicon quantum dots may form the basis of future quantum computers that could solve problems impossible for today’s computers.

Green Technology

Tellurium continues to be important for solar energy. Researchers are working to increase the efficiency of thermoelectric materials containing tellurium, which could help recover waste heat from industrial processes and vehicle engines.

Medical Advances

Boron neutron capture therapy (BNCT) shows promise for treating certain types of cancer. This technique uses boron’s ability to absorb neutrons to target cancer cells specifically, potentially reducing side effects compared to traditional radiation therapy.

Conclusion

Metalloids are truly special elements that bridge the gap between metals and non-metals. Their unique properties make them essential for modern technology, from the silicon in your computer to the boron in your heat-resistant cookware.

While some metalloids present safety challenges, their benefits have transformed our world. As technology advances, these versatile elements will continue to play crucial roles in electronics, energy, medicine, and beyond.

Next time you use your smartphone or admire a solar panel installation, remember the metalloids working behind the scenes to make these technologies possible!