Bismuth

Bismuth is a shiny metal.

It can look like a rainbow. This happens when a thin layer forms on it. It can also look pink.

People have used this metal for a long time. In the past, people thought it was tin or lead.

It is a brittle metal. This means it can break easily.

Bismuth is safer than lead. Because of this, people use it to replace lead. It is also used to help people feel better.

Some medicine uses it to help your tummy.

When it turns from liquid to solid, it grows. This helps make things like metal letters for printing. It is a very special metal.

Bismuth is a unique metal.

It has a silvery-white color when it is first made. However, it often looks pink. This is because a thin layer forms on its surface. If you heat it, the metal can show many colors. This rainbow look is called iridescence.

This happens because of how light hits the thin layer on the metal.

People have known about bismuth since ancient times. In the past, people often confused it with lead or tin. Bismuth is a brittle metal. This means it can break or snap easily. It is also very special because it expands as it turns from a liquid to a solid. This trait helps make metal letters for printing.

Bismuth is much safer than lead. Many people use bismuth to replace lead in different tools. It is also used in medicine. Some medicines use bismuth to help treat an upset stomach.

Scientists also study it. For a long time, they thought it was stable. In 2003, they found it is actually slightly radioactive. It stays this way for a very, very long time.

Bismuth is a very special metal with the symbol Bi. It has the atomic number 83 on the periodic table.

This metal is a post-transition metal. It is part of a group called pnictogens. This group also includes arsenic and antimony. Bismuth is quite heavy. It is about 86% as dense as lead.

One amazing thing about it is how it reacts to light. When it is freshly made, it looks silvery-white. However, a thin layer forms on the surface. This layer usually gives the metal a rosy color. If you heat it, the metal can show many colors. This rainbow effect is called iridescence. It happens because of thin-film interference. This is when light waves bounce off the surface in a special way.

Bismuth has some very unusual physical traits. It is a brittle metal. This means it can snap or break easily. It is also the most diamagnetic element known. This means it is pushed away by magnetic fields.

Bismuth is also hard to use to move heat. It has one of the lowest thermal conductivities of any metal. This means heat does not move through it very fast. Another strange thing happens when it freezes. Most things shrink when they get cold. Bismuth actually expands by 3.32% as it turns from a liquid to a solid.

This expansion is very helpful. It was used to make metal type for printing. The metal would expand to fill every tiny corner of a mold.

People have known about bismuth since ancient times. No single person is credited with finding it. In the past, it was often confused with tin or lead. This was because it looks similar to those metals.

The name "bismuth" might come from old German words. These words might mean "white mass." A man named Georgius Agricola wrote about it in 1546. He said it was a distinct metal. Later, scientists like Carl Wilhelm Scheele helped prove it was different from lead. In 1753, Claude François Geoffroy also showed it was its own unique element. This helped people understand exactly what it was.

Bismuth is very useful in our world today. It is much less toxic than lead. Because of this, many people use bismuth alloys to replace lead.

About one third of the world's bismuth is used for this. It is also used in cosmetics and pigments. Some medicines use bismuth to help treat diarrhea.

Most bismuth is not mined by itself. Instead, it is found while refining other metals. It is a byproduct of mining copper, tin, or tungsten. In 2016, about 10,200 tonnes were mined. Another 17,100 tonnes were made by refining. This shows how much we rely on this metal in many different ways.

Scientists also study bismuth to learn about the universe. For a long time, people thought bismuth was stable. They thought it was the heaviest element that did not decay. However, researchers in France found something new in 2003. They discovered that bismuth-209 is actually slightly radioactive. It undergoes something called alpha decay. This means it breaks down very, very slowly. Its half-life is a billion times longer than the age of the universe.

This makes it very safe for most jobs. Even though it is radioactive, it is still used in medicine. Some special versions of bismuth are even used to help treat cancer.

Bismuth is a unique chemical element with the symbol Bi and the atomic number 83.

It is classified as a post-transition metal and belongs to a group of elements called pnictogens. This group also includes arsenic and antimony. Bismuth is highly valued because it possesses unusual physical properties that are rare among metals. It is also notable for having a much lower toxicity level than its neighbors on the periodic table. This makes it a safer alternative for many industrial and medical applications.

The physical behavior of bismuth is quite remarkable. It is a brittle metal that appears silvery-white when it is first produced. However, the surface quickly undergoes oxidation, which often creates a rosy tint. If the metal is heated, further oxidation occurs. This creates a thin layer on the surface that causes thin-film interference. This phenomenon results in a vivid, iridescent appearance with a rainbow of colors.

Bismuth also possesses extreme physical traits. It is the most diamagnetic element known, meaning it is repelled by magnetic fields. Additionally, it is one of the least thermally conductive metals. This means it does not transfer heat as easily as most other metals.

One of the most distinctive processes involving bismuth is how it changes state. Most substances shrink as they cool and solidify. Bismuth does the opposite. It expands by 3.32% during solidification. This expansion happens because the liquid phase is denser than the solid phase. This property is shared by only a few other substances, such as water and silicon.

This expansion was historically useful for casting printing type. The metal would expand to fill every corner of a mold perfectly. Bismuth crystals also grow in a unique way. They often form "hopper crystals" with a spiral, stair-stepped structure. This happens because the edges of the crystal grow faster than the interior edges.

Bismuth has been recognized since ancient times, so no single person is credited with its discovery. In the past, it was frequently confused with lead or tin due to its appearance. The name "bismuth" is of uncertain origin. It may come from 16th-century German words meaning "white mass."

In 1546, Georgius Agricola identified it as a distinct metal from tin and lead. Later, scientific progress helped clarify its identity. Johann Heinrich Pott began this work in 1738. Carl Wilhelm Scheele and Torbern Olof Bergman also helped distinguish bismuth from lead. Finally, in 1753, Claude François Geoffroy proved that bismuth was a separate element from both lead and tin.

Today, bismuth is a vital part of global industry. A large portion of its use is driven by environmental safety. Because bismuth is much less toxic than lead, it is used to create safer alloys. About one third of global bismuth production is now dedicated to replacing lead in various products.

Bismuth compounds also make up about half of the global production. These are used in pigments, cosmetics, and certain pharmaceuticals. For example, bismuth subsalicylate is a common medicine used to treat diarrhea.

The metal is also used in specialized medical treatments. Scientists use bismuth-213 in targeted alpha therapy to help treat certain types of cancer.

Most bismuth is not obtained through direct mining of the element itself. Instead, it is produced as a byproduct during the refining of other metals. It is often found within the ores of copper, lead, tin, molybdenum, and tungsten. One common method to separate it is the Kroll-Betterton process. Another method is the electrolytic Betts process. To reach high purity, the metal may be reacted with chlorine gas. This converts impurities into chlorides while leaving the bismuth unchanged. In 2016, the world produced 10,200 tonnes of bismuth through mining and 17,100 tonnes through refining.

For a long time, scientists believed bismuth was the heaviest stable element. They thought its nucleus would never decay. However, research in 2003 at the Institut d'astrophysique spatiale in France changed this understanding. Researchers discovered that the only primordial isotope, bismuth-209, is actually slightly radioactive. It undergoes alpha decay, which is a process where the nucleus emits an alpha particle.

Even though it is radioactive, its half-life is incredibly long. It is roughly a billion times longer than the estimated age of the universe. Because it decays so slowly, it is still treated as a stable element for almost all industrial and medical uses.