By Emily Newton 
We encounter a variety of different elements every single day, from the fluoride in your toothpaste to the sodium and chlorine in your table salt, but some of them are more common than others. Today, we’re going to take a closer look at some elements that you might not encounter — or want to encounter — during your daily activities: the semimetals. What are metalloids and where might you use them during your everyday activities?
Metalloids, also known as semimetals, fit between the metals and nonmetals on the periodic table, but what are metalloids, really? They are tricky to define because they have what is known as intermediate properties, meaning they can present properties that could belong to either the metals or nonmetals group. There’s no definitive answer as to which group these elements belong. For most scientists, it’s a judgment call.
Yes, you read that right. Even scientists have trouble answering the question ‘what are metalloids?’
The elements ‘officially’ included in the semimetals group are:
| Common Metalloids | Uncommon Metalloids |
|---|---|
| Silicon | Antimony |
| Boron | Tellurium |
| Arsenic | Polonium |
| Germanium |
Silicon is the second most abundant element found in the Earth’s crust. The only element more abundant is oxygen.
Another thing that is strange about the semimetals on the periodic table is that they don’t appear on the periodic table in a straight vertical or horizontal line – their group line is diagonal.
Elements belonging to the semimetals group can be strange. They look like brittle metals, but their chemical behavior is distinctly non-metallic. They can, and generally do, form alloys with the metals around them, making them stronger and giving them metallic properties.
Whether or not these elements present metallic properties depends on the substances with which they’re interacting. Boron, for example, will act like a nonmetal when interacting with the volatile element sodium but will behave like a metal element when interacting with fluorine.
One of the most coveted properties of metalloids is the fact that under certain conditions, they can act as conductors. This trait, of only conducting electricity under certain circumstances, is known as semiconductivity.
Where might you find these elements during your daily activities? Most of them are more common than you might think. What are some uses of metalloids in our daily life?
Silicon is easily one of the most useful elements on the planet. It’s the second most abundant element in the Earth’s crust and gets its name from silex, the Latin word for Flint. It earned this moniker because it is gray and metallic when in a crystalline form, resembling the stone it borrows its name from. If you’re reading this article on any sort of electronic device — cell phone, laptop, computer or tablet— then you’re utilizing silicon. Its natural abundance in the Earth’s crust makes it perfect for widely manufactured materials like electronics.
The human-made polymer silicone is a favored material from an environmentalist perspective because of its durability. It makes a viable alternative to most plastic products. It is not typically commercially recyclable or biodegradable, but its structure makes it break down less easily than other materials. This means it pollutes the environment less, which is essential as microplastics are becoming increasingly worrisome.
Boron dates back to the early 1800s when researchers combined boric acid with potassium, isolating boron as a brand new element. The element gets its name from a combination of two words — buraq In Arabic and burah in Persian. Both are the languages’ respective words for borax.
The metalloid is essential for controlling flames because it has fire-retardant properties. Throwing it on wood or other materials eliminates its combustible traits. The right mixture can also create boric acid, which firefighters can use on buildings and in forests to release non-toxic smoke with a peak temperature. It’s so effective that it could control commercial fires from coal plants, which is what makes it relatively expensive to produce.
Arsenic is one element that you really don’t want to run into and has developed a bad reputation because of its historical use and polluting qualities. Sometimes, it appears in unfortunately high quantities in waterways, leading to long-term health conditions in affected areas. This element is incredibly toxic and is perhaps best known for its use as a poison for assassinations.
Being poisonous doesn’t mean that there aren’t any uses for this element, however. It’s time to reframe arsenic and notice its usefulness — while practicing reasonable caution.
Antimony dates back to ancient Egypt, though scientists didn’t officially classify it until 1707. Its name comes from two Greek words — anti and monos. Combined, the two words mean “not alone” because it is very rarely found on its own in nature. Germanium, on the other hand, didn’t get isolated until 1886. Both have similar uses, so they often get lumped into the same groups.
These two examples of metalloids are not common, making most commonplace uses of them rather expensive. Additionally, most of the world’s antimony, for example, is monopolized in China, exacerbating potential cost concerns.
Miners discovered tellurium by accident while trying to extract antimony from gold. You’ll occasionally find tellurium on its own in nature, but it prefers to spend its time in ores like sylvanite and calaverite. Strangely, even the most acute exposure to tellurium will cause a weird side effect known as tellurium breath. It makes your breath smell like garlic, and it’s unfortunately coupled with other symptoms like nausea and headache. It might be why its uses are minimal.
Marie Curie, the famous chemist, discovered polonium and named it for her home country of Poland. The bold choice caused political tension after Russia’s long-standing domination over the country. Not many metalloids can claim to have this much of a social and political impact. This element is one you really don’t want to encounter because it’s highly radioactive. It’s also one of the rarest elements in this family.
Bismuth is a relatively rare metalloid discovered in the early 16th century. Its name is derived from the German word “Weisse Masse,” which loosely translates to “white mass.” Notable for its lower toxicity compared to other heavy metals, bismuth has gained attention for its use in various applications, including pharmaceuticals and cosmetics.
Selenium is a metalloid discovered in 1817 by the Swedish chemist Jöns Jacob Berzelius. Its name is derived from “Selene,” the Greek goddess of the moon. Selenium is a semimetal known for photoconductive properties and is crucial in various industrial processes.
Thallium is a soft, bluish-white metalloid discovered in 1861 by the British chemist Sir William Crookes. The name “thallium” is derived from the Greek word “thallos,” meaning “green shoot,” in reference to the bright green spectral line it produces when heated.
Thallium is known for its toxicity and has historically been used in various applications, including murder. The material is tasteless and odorless, making it a notoriously difficult-to-detect poison. Despite its potentially harmful nature, thallium has unique properties that make it useful in certain specialized fields.
Some of these elements are definitely more common than others, but they all have their uses. The malleability, radioactivity and availability of metalloids make them versatile in application. It’s possible the future will find even more ways to manipulate them for innovations.
The next time you pick up your cell phone or boot up your computer, remember to thank Jons Jacob Berzelius who discovered silicon in 1824. The modern computing age wouldn’t be possible without him.
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