Named after Thor, the Norse god of thunder, this metal packs a truly thunderous punch of energy. A single kilogram of thorium can generate as much electricity as 3,500 tons of coal. And there's three to four times more of it on Earth than uranium.
Thorium is a silvery-white, soft, and ductile metal. It's mildly radioactive: Th-232 has a half-life of 14 billion years — longer than the age of the universe itself. You'll find traces of it in granite, beach sand, and even your backyard soil. Today, scientists see thorium as the nuclear fuel of the future — safer and more abundant than uranium.
In 1829, Swedish chemist Jons Jacob Berzelius isolated a new element from the mineral thorite. He named it after Thor, the god of thunder in Norse mythology. For decades, thorium was mainly used in gas lamp mantles: thorium oxide glowed brilliantly white when heated.
Today, thorium is back in the spotlight as a next-generation nuclear fuel. India, China, and Canada are building experimental thorium reactors. They promise fewer radioactive waste products, inherently safer operation, and near-zero potential for weapons proliferation.
Thorium is a mildly radioactive metal. Th-232 emits alpha particles that cannot penetrate skin. However, inhaling thorium dust is very dangerous: it accumulates in the lungs and bones, increasing cancer risk. Thorium powder can ignite spontaneously in air. Working with thorium requires a respirator, fume hood ventilation, and dosimetric monitoring. It must be stored in sealed containers.
Thorium-232 has a half-life of 14 billion years. That's longer than the universe has existed (13.8 billion years). Thorium atoms formed when Earth was born are still decaying right now.
One kilogram of thorium can produce as much electricity as 3,500 tons of coal. Earth's thorium reserves could power humanity for millions of years.
There is 3 to 4 times more thorium on Earth than uranium. The largest deposits are in India, Brazil, Australia, and the USA. India alone has over 900,000 tons of thorium reserves.
A thorium reactor cannot explode like Chernobyl. If cooling fails, the chain reaction stops on its own. And the waste products cannot be turned into nuclear weapons.
Until the 1950s, a toothpaste called 'Doramad' was made with thorium — advertised as 'radioactive whitening for your teeth.' Back then, the dangers of radiation were poorly understood.
Gas lamp mantles containing thorium oxide lit the streets of Europe for over 100 years. When heated, ThO₂ produces a brilliant white glow — brighter than any other oxide.
| Isotope | Mass (u) | Abundance | Half-life | Decay |
|---|---|---|---|---|
228Th☢ | 228.028741 | synthetic | 1.9116 years | α |
230Th☢ | 230.033134 | synthetic | 75380 years | α |
232Th☢ | 232.038055 | 100.00% | 1.405×10¹⁰ years | α |
Analysis of thorite