Thulium

Thulium is a rare metal.

It looks like bright silver. It is a very soft metal. You can even cut it with a knife.

A scientist named Per Teodor Cleve found it. It is hard to find in the ground. We use it to make lasers. It can also be in money. It glows blue under special light. This helps stop people from making fake money.

Thulium is a rare metal.

It belongs to a group called lanthanides. It is the second-least common metal in this group. You can find it in minerals like monazite.

A Swedish chemist named Per Teodor Cleve found it in 1879. He named it after Thule. Thule was an old name for parts of Scandinavia.

Thulium is a bright, silvery-gray metal. It is quite soft. You can actually cut it with a knife. It tarnishes slowly when it touches air. It can also burn easily at 150°C. This can cause fires or even small explosions.

We use thulium in many ways. It is used in lasers for surgery. These lasers help doctors work on body tissue. Some thulium is used in portable X-ray machines. These machines help doctors see inside the body. Thulium also glows blue under ultraviolet light. This is why it is put in euro banknotes. The glow helps stop people from making fake money.

Thulium is a rare and interesting chemical element. It has the symbol Tm and the atomic number 69. It belongs to a group of metals called the lanthanides. In fact, it is the thirteenth element in this series. Thulium is the second-least common lanthanide found in the Earth's crust. Only the radioactive element promethium is less abundant.

This metal is quite special because it is very hard to find. Even though it is rare, it has many important uses in science and medicine.

This metal has a bright, silvery-gray luster. It is a soft metal that you can actually cut with a knife. Because it is soft, scientists call it malleable and ductile. This means it can be shaped or stretched without breaking. However, thulium does not stay shiny forever. It tarnishes slowly when it is exposed to the air. If it gets hot, specifically at 150°C, it can burn quite easily. This can even cause small explosions if the metal is in dust form.

A Swedish chemist named Per Teodor Cleve discovered thulium in 1879. He was looking for impurities in the oxides of other rare earth elements. He found two new substances while studying a mineral called erbia. One was holmia, and the other was thulia. He named thulium after Thule, which was an old name for Scandinavia.

It took a long time to get a pure sample. Charles James first obtained nearly pure thulium in 1911. Later, in 1936, Wilhelm Klemm and Heinrich Bommer obtained the metal itself.

Thulium is found in several different minerals around the world. It is often found in minerals like monazite, xenotime, and euxenite. It also appears in a mineral called gadolinite.

Most thulium comes from monazite ores found in river sands. Today, a principal source for this metal is the clays in southern China. In 2001, the total world reserves were about 100,000 tonnes. Thulium is quite expensive to buy. For example, in 2005, pure thulium metal powder cost about $70 per gram.

We use thulium in many clever ways in our daily lives. It is used as a dopant in lasers. These lasers are helpful for doctors during surgery on body tissue. Some thulium is also used in portable X-ray devices. Scientists use the isotope thulium-170 to help make these machines work. Another cool fact is that thulium glows a bright blue under ultraviolet light. Because of this glow, thulium is put into euro banknotes. This helps people know the money is real and not a fake.

Thulium is a chemical element with the symbol Tm and atomic number 69. It is the thirteenth element in the lanthanide series of metals. Thulium is a rare substance found in the Earth's crust. In fact, it is the second-least abundant lanthanide. Only the radioactive element promethium is less common.

This element is valued for its unique physical and chemical properties. Despite its rarity and high cost, it plays vital roles in modern technology. It is used in medical tools and advanced laser systems.

As a metal, thulium has a bright, silvery-gray luster. It is quite soft and can be cut with a knife. Scientists measure its hardness between 2 and 3 on the Mohs scale. This makes it both malleable and ductile. Malleable means it can be hammered into sheets. Ductile means it can be drawn into wires. However, thulium reacts with its environment. It tarnishes slowly when exposed to air. If it reaches 150°C, it can burn readily to form thulium(III) oxide. Thulium dust is particularly dangerous because it can cause fires or explosions.

Thulium shows different magnetic behaviors depending on its temperature. It is ferromagnetic below 32K. This means it can be strongly attracted to magnets. Between 32K and 56K, it becomes antiferromagnetic. Above 56K, it is paramagnetic. The metal also exists in two different structural forms called allotropes. These are the tetragonal α-Tm and the more stable hexagonal β-Tm. In chemical solutions, thulium ions often form coordination complexes. In these complexes, a single thulium ion is surrounded by nine water molecules. These specific ions exhibit a bright blue luminescence.

The discovery of thulium is a story of careful scientific observation. In 1879, Swedish chemist Per Teodor Cleve identified the element.

He was studying the oxides of other rare earth elements. He found two new components in the mineral erbia. He called them holmia and thulia. Thulium was named after Thule, an ancient name for Scandinavia. It took many years to achieve high purity. Charles James obtained nearly pure thulium in 1911 using fractional crystallization. He performed 15,000 operations to ensure the material was homogeneous. Later, in 1936, Wilhelm Klemm and Heinrich Bommer obtained the pure metal.

Thulium is quite difficult to find in nature. It is never found in a pure form on its own. Instead, it exists in small amounts within various minerals. It is frequently found in monazite, xenotime, and euxenite. It also occurs in the mineral gadolinite.

Most thulium is extracted from monazite ores found in river sands. Today, much of the supply comes from ion adsorption clays in southern China. The element's abundance in the Earth's crust is only 0.5 mg/kg. In 2001, total world reserves were estimated at 100,000 tonnes. Because it is so rare, it is very expensive. In 2005, 99%-pure thulium metal powder cost approximately $70 per gram.

Modern technology relies on thulium for several specialized tasks. One major use is as a dopant in solid-state lasers. A dopant is a substance added to change a material's properties. Thulium-doped YAG lasers are highly efficient. They operate at a wavelength of 2010 nm. These lasers are useful for surgery because they can remove tissue with minimal damage. Another application is in portable X-ray devices. Scientists use the isotope thulium-170 for this purpose. This isotope has a half-life of 128.6 days. These X-ray tools are used in medicine, dentistry, and industrial inspections.

Thulium also has interesting uses in security and science. The element fluoresces with a blue color under ultraviolet light. Because of this unique glow, thulium is included in euro banknotes. This helps prevent counterfeiting by making the notes harder to fake. In biology, thulium has a low level of toxicity. It does not have a significant biological role in living things. However, soluble thulium salts can be mildly toxic if injected. In humans, the element is mostly found in the liver, kidneys, and bones. Humans typically consume only a few micrograms of thulium each year.