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Osmium

physical science Maturity 7-9 Next article →

Osmium is a very special metal found in the Earth's crust.

Osmium 1-crop
Osmium 1-crop

It belongs to a family called the platinum group. This metal is a hard, blue-gray substance that is also very brittle. One of its most amazing facts is its density. Osmium is the densest stable element we know about. It is about twice as heavy as lead.

Osmium cluster
Osmium cluster

Because it is so heavy and hard, it is very useful for certain jobs. Manufacturers often mix it with other metals to make alloys. They combine it with platinum or iridium to make parts that must last a long time. These mixes are used for the tips of fountain pen nibs and for electrical contacts.

Working with osmium can be a hard job because of its physical properties. It is very difficult to machine, form, or work into different shapes. This is because it has a very high melting point. In fact, its melting point is the fourth highest of all elements. It is also very hard and does not compress easily. When osmium reacts with other things, it can change its state. One common form is osmium tetroxide.

Osmiumtetroxide1
Osmiumtetroxide1

This is a solid that turns into a gas very easily. It has a very strong and unpleasant smell. This is how the metal got its name. The name comes from the Greek word "osme," which means smell.

People discovered osmium in 1803.

Platinum nuggets
Platinum nuggets

Two men named Smithson Tennant and William Hyde Wollaston found it in London, England. At the time, scientists were studying platinum. They noticed a dark, leftover residue when they dissolved platinum in acid. Some people thought this residue was just graphite. However, Tennant studied the residue more closely. He realized it contained new metals. He identified both iridium and osmium in that black powder. He shared his findings in a letter to the Royal Society in 1804.

Osmium is quite rare in our world. It is one of the least common stable elements in the Earth's crust. You can find it in places like South Africa, Russia, and Canada. It is often found near nickel and copper deposits.

Osmium cluster
Osmium cluster

Sometimes it is found in impact craters from space. Most osmium is obtained as a byproduct of mining other metals. Workers find it in something called anode mud. This mud settles at the bottom when copper and nickel are refined. Scientists then use special methods to separate the osmium from the other metals.

Osmium is also helpful for understanding the history of our planet. It has several different versions called isotopes. One specific isotope is used for rhenium-osmium dating. This helps scientists figure out the age of rocks on Earth. It can even help date rocks that came from space, called meteoric rocks. By looking at these metals, we can learn how the Earth's mantle changed over a very long time. This connects the tiny atoms of osmium to the huge history of our entire world.

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File:Osmium 1-crop.jpg
Osmium 1-crop.jpg
File:Osmiumtetroxide1.jpg
Osmiumtetroxide1.jpg
File:Platinum nuggets.jpg
Platinum nuggets.jpg
File:Osmium cluster.jpg
Osmium cluster.jpg
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