Chem Explorers

Iridium: The Rare and Remarkable Element with Unique Properties

Iridium is a rare, lustrous, and hard transition metal belonging to the platinum family. Its chemical symbol is Ir, and its atomic number is 77.

It is one of the densest metals known, with a melting point of 2,447C and a boiling point of 4,427C. Iridium is also highly corrosion-resistant and is often alloyed with other metals to enhance their hardness and durability.

Natural Occurrence of Iridium

Iridium is a rare element that occurs in very small quantities in the Earth’s crust. It is found primarily in sediment deposits and river sands where it is often associated with other platinum group metals such as platinum, palladium, osmium, and ruthenium.

Iridium is also produced as a byproduct during the nickel refining process.

History of Iridium Discovery

Iridium was discovered in 1803 by Smithson Tennant, a British chemist, while he was studying platinum ores at the Royal Institution in London. Tennant named the element iridium after Iris, the Greek goddess of the rainbow, due to the different colors that iridium compounds produced when exposed to light.

The first commercial production of iridium was in the late 19th century by Ignatz von Liebig, a German chemist.

Identification of Iridium

Iridium is a member of group 9 and period 6 of the periodic table. Its atomic number is 77, and its CAS number is 7439-88-5.

Iridium has an atomic mass of 192.217 g/mol and a molar mass of 192.217 g/mol. It is classified as a transition metal and belongs to the d-block.

Physical Properties of Iridium

Iridium has many unique physical properties that make it valuable to many industries. It is a very hard and dense metal with a density of 22.56 g/cm.

Iridium is also highly resistant to corrosion and is one of the most chemically stable elements known. It has a melting point of 2,447C and a boiling point of 4,427C, making it one of the highest melting points of all elements.

Chemical Properties of Iridium

Iridium has a variety of chemical properties that make it a useful element in many fields. It has nine known oxidation states between -3 and +9.

Iridium’s electronic configuration is [Xe] 4f14 5d7 6s2, and its electron affinity is 150.94 kJ/mol. Its ionization energy is 880.33 kJ/mol.

Uses of Iridium

Iridium has many practical applications due to its unique combination of physical and chemical properties. One of its most important uses is in the production of electrical components such as electrical contacts and spark plugs due to its resistance to corrosion and high melting point.

Iridium is also used in the manufacture of crucibles and other high-temperature equipment, and it is alloyed with platinum to make high-strength surgical implants. Another critical use of iridium is in the production of catalytic converters used in vehicles to help reduce harmful emissions.

This is due to iridium’s ability to facilitate the conversion of harmful pollutants into less harmful substances. Iridium is also used as a catalyst in the chemical industry and in the production of fine chemicals such as pharmaceuticals.


In conclusion, iridium is a rare and valuable element that has several unique properties useful in many fields like electronics, medical technology, and catalysis. With its high melting point, resistance to corrosion, and ability to promote chemical reactions, many essential industries rely on iridium.

Understanding its properties and history helps us appreciate its importance in modern-day applications. Iridium is a crucial element in several industries due to its exceptional physical and chemical properties.

It is one of the densest and most corrosion-resistant metals known, with the highest melting point of all elements. In this article, we will delve deeper into the uses and applications of iridium, as well as some interesting facts about this valuable element.


Uses of Iridium

Due to its resistance to corrosion, iridium is widely used in industrial applications. It is often used as an alloying agent with other metals, such as platinum, to enhance their properties.

For example, iridium alloyed with platinum is used to make high-strength meter bars used in precision measurements. Iridium is also used in various bearings, compasses, pen tips, and spark plug contacts.

Medical Applications of Iridium

The medical field uses iridium in various treatments due to its unique properties. For instance, iridium is used in prostate cancer therapy, a procedure that involves implanting radioactive iridium seeds directly into the prostate gland to destroy cancer cells.

Additionally, iridium is used in radiotherapy for breast cancer treatment. The radiation emitted by iridium is carefully targeted to cancerous cells, killing them while causing minimal damage to surrounding healthy tissue.

Iridium also helps alleviate hearing loss in the elderly, where it is utilized in the production of cochlear implants, which take advantage of iridium’s superior biocompatibility.

Toxicity of Iridium

Iridium is a naturally occurring element and is generally nontoxic. It has a low level of reactivity and poses limited health hazards to humans.

The metal is relatively inert chemically, so it is not readily absorbed by the body. However, iridium compounds may cause irritation when it comes into contact with skin or eyes.

Inhalation of iridium dust may also cause respiratory issues. It is worth noting that the toxicity of iridium is currently being studied and may be subject to change.

Interesting Facts

Iridium has many fascinating properties and stories. For one thing, iridium is typically found in very thin layers in the Earth’s crust, which is what makes it so rare and valuable.

This element is also found in sedimentary rocks, where it can be found in association with other platinum group metals. However, the most interesting fact about iridium is its connection to the demise of the dinosaurs.

It is believed that the Earth was struck by an asteroid around 66 million years ago, which caused an extinction event. The asteroid impact released a vast amount of iridium into the atmosphere, which is why a thin layer of iridium is found in rocks from the Cretaceous period.

This has allowed scientists to study and understand the event better and its aftermath. While iridium is highly valuable and its unique properties make it a favorite for several industries, it is important to note that it comes with a hefty price tag.

Today, the cost of pure iridium is high, with the price per gram fluctuating along with demand and supply.


In summary, iridium’s unique physical and chemical properties make it incredibly valuable in several industries, from industrial and medical applications. Its high resistance to corrosion and exceptional biocompatibility make it an ideal element for medical implants, while a wide variety of industrial applications take advantage of its hardness, high melting point, and conductivity.

While this element does pose some health hazards, these risks are relatively low. As such, the uses of iridium are limited perhaps only by its availability.

In conclusion, iridium is an essential element with exceptional physical and chemical properties, widely used in various industries, particularly in industrial and medical applications. It is corrosion-resistant, biocompatible, and has unique characteristics, such as its rarity and connection to the extinction of dinosaurs.

While iridium may pose some health risks, they are relatively low, making it a safe element to use. As a result, the importance of iridium cannot be underestimated as a valuable resource that is required for various critical applications.


– What is iridium used for?

Iridium is used for various purposes, including producing electrical components, surgical implants such as cochlear implants, and catalytic converters in the automobile industry to reduce emissions.

– Is iridium toxic to human beings?

Iridium is generally considered safe and nontoxic.

However, it may cause skin irritation and respiratory issues when inhaled. – Why is iridium so expensive?

Iridium is rare and difficult to mine, making it expensive. It is present in very small quantities in the Earth’s crust, and mining it is a time-consuming and costly process.

– What makes iridium unique?

Iridium has exceptional physical and chemical properties.

It has the highest melting point of all elements, high resistance to corrosion, and great biocompatibility with human tissue. – What is the connection between iridium and the extinction of dinosaurs?

The Earth was struck by an asteroid around 66 million years ago, releasing large amounts of iridium into the atmosphere. This event resulted in an extinction event that wiped out the dinosaurs.

Popular Posts