Everyday Uses of Actinides

We’re coming to the end of the rare elements on the periodic table. The last section, known as actinides, rests on the very bottom of the table and includes all the elements with atomic numbers between 90 and 109. These aren’t elements that you’ll find in your kitchen though — or even in a typical science lab unless you happen to live near a particle accelerator. Let’s take a look at the actinides’ properties, how abundant they are and what sets them apart from the other elements on the periodic table.

Actinides Properties Explained

In spite of the fact that 15 elements fall under the actinides classification, but you can only five of them in nature. For decades, the periodic table ended with uranium, with an atomic number of 92. The radioactive element was the heaviest element ever discovered, and scientists didn’t think that they would ever find anything heavier — until the discovery of neptunium in 1940.

Fun fact: Every element in the actinides group that comes after uranium is classified as transuranium, or heavier than uranium.

The elements in the actinides group include:

Atomic No. 89-93	Atomic No. 94-98	Atomic No. 99-103
Actinium	Plutonium	Einsteinium
Thorium	Americium	Fermium
Protactinium	Curium	Mendelevium
Uranium	Berkelium	Nobelium
Neptunium	Californium	Lawrencium

Two of these are found in the Earth’s crust — thorium and uranium. Plutonium and neptunium are found in uranium ore veins. Actinium and protactinium both appear during the decay of thorium and uranium.

All of the rest of these elements are considered synthetic and are produced in a lab or a particle accelerator.

Fun fact: There exist elements that are heavier than Lawrencium, the last actinide in the family, but they belong to the lanthanide, or rare earth element, group.

Chemical & Physical Traits

Every element in the actinides family is highly radioactive. There have, to this day, been no stable isotopes discovered for any actinides. The metals, when exposed to air, tarnish quickly and can even ignite. They also tend to be very malleable and ductile — easy to shape and form — though you don’t want to handle any of these elements with your bare hands. They are all solid at room temperature, and when placed in boiling water or diluted acid, they produce hydrogen gas.

All of these elements are electropositive. When they react with other elements, they give up their electrons fairly easily to form positive ions. Each element, except actinium, has multiple allotropes, different physicals forms, that can be found or created. Plutonium has at least six allotropes!

All of the members of this elemental family are also paramagnetic. This means that while they can demonstrate some weak attraction to magnetic poles, they are not inherently magnetic and don’t retain any magnetism once you remove the magnetic field.

Real-Life Applications

Due to the actinides properties, you won’t encounter most of these elements in your everyday life. That doesn’t mean they don’t have any real-life applications, however.

Uranium

Uranium is the most common rare earth element in the actinides family. Its various isotopes have applications across a variety of different industries. All these isotopes — really, all of the elements in the actinides family — are inherently radioactive and have various half-lives. The term “half-life” refers to the amount of time it takes for half of a sample to decay. The most abundant isotope, uranium-238, has such a long half-life that half of the isotope around today has been here since the birth of our planet, roughly 4.5 billion years ago.

Uses For Uranium

• Power generation: Uranium-235 is the only fissionable isotope that occurs naturally on the planet. In a nuclear power plant, this fission reaction can generate clean energy.
• Weaponry: Perhaps the most famous use for uranium is in nuclear weaponry. That same fission reaction that creates clean energy can also release massive amounts of destructive power.
• Ballast, ammo and armor: Once use depletes uranium’s radioactivity, what’s left behind is an ultradense metal. You’ll find depleted uranium in ammunition, armor and as ballast for ships.

Thorium

Thorium is probably the most common of the actinides — but that doesn’t mean there’s a lot of it to go around. On average, thorium mines will only produce a few hundred tons of it every year.

Uses For Thorium

• Nuclear fuel: Uranium-235 might be the only fissionable fuel, but it isn’t the only option. By bombarding thorium-232 with neutrons, it becomes thorium-233, which then decays into uranium-233.
• Welsbach mantle: Thorium is also used in a type of gas lantern known as a Welsbach mantle. When heated with a gas flame, it glows with a brilliant white light.
• Crucibles: Thorium has an incredibly high melting point of 3,100 F, and it boils at 8,100 F, making it an excellent choice for high-temperature crucibles.

Plutonium

Plutonium is another fissionable actinide, but it doesn’t occur naturally in the Earth’s crust. Instead, it’s a byproduct of the decay of neptunium-238. An interesting actinide fact: Scientists discovered it in 1941, but the information didn’t become widespread until 1946, after World War II.

Uses For Plutonium

• Spacecraft power: Plutonium is a popular choice for spacecraft sent on long-term missions. The Curiosity rover, currently exploring the surface of Mars, uses a radioisotope thermoelectric generator powered by 4.8 kilograms of plutonium-238.
• Nuclear weaponry: Similar to uranium, plutonium also finds uses in the production of atomic weaponry.
• Pacemakers: While you won’t find a plutonium-powered pacemaker anymore, it was an option for decades because it made the devices last longer.

Californium

Californium is another actinide that doesn’t occur naturally on the planet. Instead, it’s what’s left over when curium-242 gets bombarded with helium ions. It doesn’t last long, though — at least when compared to the other actinides. Californium-252 only lasts around 2.6 years, and californium-245 has a half-life of only 45 minutes.

Uses For Californium

• Identifying precious metals: Californium produces neutrons. When included in a detection device, it can find and identify precious metals like gold and silver instantly, without having to send samples out to a lab.
• Moisture gauges: Those same neutrons are also valuable for detecting oil and water layers in wells.
• Detecting metal fatigue: Californium neutrons can also detect metal fatigue in aircraft, preventing small problems from becoming big ones.

Curium and Americium

Curium gets its name from Marie Curie and her husband, Pierre. Marie was one of the world’s foremost chemists of her time, accelerating much of our understanding of radioactive isotopes. Both americium and curium don’t occur naturally and have minimal applications.

Uses For Curium and Americium

• Spacecraft fuel: Both curium and americium generate massive amounts of energy and might be the perfect option for spacecraft fuel once we move away from plutonium-powered ships and rovers.
• Smoke detectors: Roughly 80% of smoke detectors in the United States contain some americium-241 that allows the device to find smoke in the atmosphere.
• Cancer treatments: Americium-241 is one of the radioactive isotopes used in brachytherapy for the treatment of cancer.

Conclusion

You don’t want to include actinides in your next lab experiment unless you’ve got lots of protective equipment and the proper expertise. The inherent radioactivity of these elements makes them dangerous. Marie Curie’s research notebooks are still radioactive nearly a century after her death and probably will be for another 1,500 years. Even her body is buried in a coffin lined with lead because she absorbed so much radioactivity during her life.

While Marie Curie might not have worked with the actinide that bears her name, she discovered polonium, another radioactive element that she named after her home country of Poland. Polonium is 100 times more radioactive than uranium. She would probably be fascinated to see how many new radioactive elements we’ve discovered since her death. You might not see these elements in your everyday life, but actinides properties have many applications that help make modern life and space exploration possible.

What actinides properties did you find the most interesting? Comment below to let us know!

This article originally published 05/03/2018. We updated it on 08/12/2020 to expand the section of Real Life Applications with more in-depth uses of actinides.