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Thorium

physical science Maturity 11-13 Next article →

Thorium is a bright, silver metal that is quite interesting to scientists. It is an actinide, which is a group of heavy elements.

Thorium half sandwich
Thorium half sandwich

This metal is moderately soft and can be bent or shaped. It is also malleable, meaning it can be pressed into thin sheets.

CaF2 polyhedra
CaF2 polyhedra

When thorium is exposed to the air, it changes color. It turns an olive grey color because it forms thorium dioxide. This metal has a very high melting point of 1750 °C. It is much higher than other elements like actinium or protactinium.

Kristallstruktur Uran(IV)-fluorid
Kristallstruktur Uran(IV)-fluorid

Thorium is radioactive, which means its atoms are unstable. All known versions of thorium are unstable and will change over time.

Decay Chain Thorium
Decay Chain Thorium

The most stable version is called 232Th. It has a half-life of 14 billion years. This is about as old as the entire universe! This version changes through a process called alpha decay. This starts a long chain of changes called the thorium series. This series eventually ends when it becomes a stable metal called lead.

Evolution of Earth's radiogenic heat-no total
Evolution of Earth's radiogenic heat-no total

A Swedish chemist named Jöns Jacob Berzelius discovered thorium in 1828.

J J Berzelius
J J Berzelius

He found it while studying a new mineral. This mineral was found by Morten Thrane Esmark in Norway. The mineral came from an island called Lovoya near the Langesund fjord.

Mårten Eskil Winge - Tor's Fight with the Giants - Google Art Project
Mårten Eskil Winge - Tor's Fight with the Giants - Google Art Project

Berzelius gave the metal its name after Thor. Thor was the Norse god of thunder and war. This name has helped people remember this powerful element for a long time.

Thorium is very common in our world. It is estimated to be over three times as abundant as uranium in the Earth's crust.

Seaborg in lab - restoration
Seaborg in lab - restoration

Most thorium is refined from monazite sands. It is often found as a by-product when people extract rare-earth elements. Scientists use different versions of thorium for many jobs. Some thorium is used in cancer treatments to help people. Other types are used to help scientists understand the ancient ocean.

Yellowing of thorium lenses
Yellowing of thorium lenses

Researchers use the ratio of isotopes to date old ocean sediments.

We use thorium in many things we see every day. It was once used as a light source in gas mantles.

Old thorium dioxide gas mantle - oblong shape
Old thorium dioxide gas mantle - oblong shape

It was also used in high-end camera lenses and scientific tools. Today, it is used to make magnesium stronger for different machines. It can also be used in aircraft engines and light bulbs.

Indian Point Nuclear Power Plant
Indian Point Nuclear Power Plant

Some people suggest using thorium as a new kind of fuel for nuclear reactors. This could change how we make energy in the future. It is a very useful metal with many different roles.

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🖼️ Images & Media (13)
File:Decay Chain Thorium.svg
Decay Chain Thorium.svg
File:CaF2 polyhedra.png
CaF2 polyhedra.png
File:Kristallstruktur Uran(IV)-fluorid.png
Kristallstruktur Uran(IV)-fluorid.png
File:Uranocene-3D-balls.png
Uranocene-3D-balls.png
File:Thorium half sandwich.svg
Thorium half sandwich.svg
File:Evolution of Earth's radiogenic heat-no total.svg
Evolution of Earth's radiogenic heat-no total.svg
File:Mårten Eskil Winge - Tor's Fight with the Giants - Google Art Project.jpg
Mårten Eskil Winge - Tor's Fight with the...
File:J J Berzelius.jpg
J J Berzelius.jpg
File:Old thorium dioxide gas mantle - oblong shape.JPG
Old thorium dioxide gas mantle - oblong shape.JPG
File:Seaborg in lab - restoration.jpg
Seaborg in lab - restoration.jpg
File:Indian_Point_Nuclear_Power_Plant.jpg
Indian_Point_Nuclear_Power_Plant.jpg
File:Yellowing of thorium lenses.jpg
Yellowing of thorium lenses.jpg

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