Bismuth

Bismuth has been a part of human history since ancient times. It was one of the first ten metals to be discovered, but no one knows who actually discovered it. The name bismuth likely comes from an old German word, Wismut, meaning “white mass.” Miners used to call it tectum argenti, or “silver being made,” thinking the earth was turning the substance into silver. Bismuth was confused with other elements for centuries.

In the 1500s, famous scientist Georgius Agricola noted that bismuth was different from tin and lead, based on its physical properties, but it took a while for people to realize just how distinct it was. In 1753, Claude François Geoffroy showed bismuth was chemically different from lead, getting credit for proving it was a unique element. Still, bismuth would continue to be confused with both lead and tin until modern analytical methods became available.

Bismuth is a white, crystalline, brittle metal with a pinkish tinge. Its thermal conductivity is lower than any metal, except for mercury. Of all metals, it is the most strongly repelled by a magnetic field.

Bismuth might seem a lot like lead, but it’s actually heavier and, most importantly, nontoxic. Since the 1990s, bismuth has been used as a safe replacement for lead. It's also been important in medicine. One of its most famous uses is in the pink stomach medicine, Pepto-Bismol—the active ingredient, bismuth subsalicylate, helps treat indigestion and other stomach issues. Bismuth is even used in cosmetics, giving makeup products like powders and eyeshadows a smooth, shiny finish.

Bismuth is highly versatile. It’s also used in fire sprinklers because it melts easily, which helps trigger the sprinklers when it gets too hot. That low melting point is also important for casting. Bismuth expands when it solidifies, which makes it perfect for creating sharp castings of objects that might be damaged by high heat.

Bismuth also plays a role in nuclear reactors, where it’s used as a coolant, and in thermoelectric devices, where it helps turn heat into electricity.

Bismuth is stable in air and water at ordinary temperatures. At high temperatures, it reacts with water to make bismuth(III) oxide. And when heated in air, it burns with a blue flame, forming yellow fumes of bismuth oxide. Bismuth sulfide forms naturally in bismuth ores. Bismuth oxychloride is used extensively in cosmetics. Bismuth subnitrate and subcarbonate are used in medicine.

Bismuth occurs naturally in the Earth’s crust at about twice the rate of gold. Its most important ores are bismuthinite and bismite. Peru, Japan, Mexico, Bolivia, and Canada are major bismuth producers. Much of the bismuth produced is obtained as a byproduct of refining lead, copper, and tungsten ores.