[Xe] 4f145d76s2
2, 8, 18, 32, 15, 2
2446°C, 4435°F, 2719 K
4428°C, 8002°F, 4701 K
Smithson Tennant
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Uses and Properties

Image Explanation

Renowned for its exceptional durability, iridium stands as a stellar choice for the composition of spark plugs. The defining characteristic of iridium spark plugs lies in the elevated melting point of their electrode material, fostering a combustion process that is thorough and culminating in enhanced overall performance.


Iridium is a hard, silvery metal. It is almost as unreactive as gold. It has a very high density and melting point.


Iridium: Unveiling the Diverse Applications of a Precious Element

In the vast realm of elements, Iridium (Ir) stands as a shining star, renowned for its rarity, resilience, and remarkable properties. While it might not enjoy the same fame as its counterparts, iridium plays a pivotal role across various industries, contributing to technologies that impact our daily lives. Join us as we explore the diverse and often overlooked applications of iridium, a precious element that silently shapes the world around us.


1. Spark Plugs and Automotive Performance

One of the most well-known applications of iridium lies in the automotive industry, where it serves as a crucial component in spark plugs. Iridium's exceptional durability and high melting point make it an ideal material for the electrodes in spark plugs. This results in spark plugs that can withstand extreme temperatures and ensure a complete combustion process, leading to enhanced engine performance, fuel efficiency, and longevity.


2. Catalysts for Industrial Processes

Iridium's catalytic properties find wide-ranging applications in various industrial processes. Iridium catalysts play a vital role in promoting chemical reactions, especially in processes like hydrogenation and dehydrogenation. These catalytic applications contribute to the production of chemicals, pharmaceuticals, and other essential industrial compounds, facilitating efficient and sustainable manufacturing practices.


3. Electrical Contacts in Electronic Devices

Iridium's resilience and resistance to corrosion make it an ideal material for electrical contacts in electronic devices. Its use in connectors, switches, and other electronic components ensures reliable conductivity and longevity. Iridium's ability to maintain its integrity under repeated electrical contact contributes to the efficiency and durability of electronic devices, from consumer electronics to industrial equipment.


4. Aerospace Alloys and Space Exploration

In the aerospace industry, iridium alloys play a vital role in the construction of various components. Its inclusion in alloys enhances the strength and corrosion resistance of materials used in aircraft and spacecraft. The durability of iridium alloys makes them suitable for the harsh conditions of space, contributing to the success of satellite components and other space exploration technologies.


5. X-ray Imaging and Medical Applications

Iridium has found its way into the field of medicine, particularly in the realm of diagnostic imaging. Iridium-192, a radioactive isotope of iridium, is used in industrial radiography for non-destructive testing and in medical applications for brachytherapy. Its ability to emit gamma rays makes it valuable for imaging and cancer treatment, showcasing iridium's importance in advancing healthcare technologies.


6. Investment and Numismatics

Beyond industrial applications, iridium's rarity and precious nature make it a sought-after metal for investment and numismatics. Iridium coins, often minted in limited quantities, appeal to collectors and investors who appreciate the uniqueness and scarcity of this precious metal. The beauty and rarity of iridium contribute to its status as a coveted item in the world of precious metal investments.


7. Emerging Technologies and Research

As technology advances, iridium continues to be a material of interest in emerging fields. Its unique properties, including high corrosion resistance and stability, position it as a valuable component in research and development. Iridium is explored for potential applications in areas such as advanced materials science, nanotechnology, and quantum computing, where its exceptional characteristics may unlock new possibilities.


8. Niche Applications in Jewelry and Art

The unique properties of iridium, including its hardness and resistance to corrosion, make it a fascinating material for niche applications in jewelry and art. Iridium is occasionally alloyed with other metals to create jewelry pieces that stand out for their durability and distinctive appearance. Its use in art further showcases the versatility of iridium in the hands of creative minds.


9. Corrosion-Resistant Coatings

Iridium's resistance to corrosion makes it a valuable material for coatings in various industrial applications. Components that face challenging environmental conditions, such as those in chemical processing or marine environments, benefit from iridium coatings that provide a protective layer, enhancing longevity and preventing degradation.


10. Historical Use in Fountain Pen Nibs

Historically, iridium found its way into the world of fine writing instruments, particularly in the crafting of fountain pen nibs. Alloys known as osmiridium or iridosmine, containing iridium, were utilized for their durability and wear resistance, contributing to a smooth writing experience. While less common today, this historical application highlights iridium's enduring role in craftsmanship.



Iridium, often overlooked in favor of its more glamorous counterparts, emerges as a versatile and indispensable element with applications spanning industries and technologies. From the roar of engines with iridium spark plugs to the delicate nuances of medical imaging, iridium silently contributes to the advancements that define our modern world. As technology continues to evolve, iridium's unique properties position it as a material of enduring value, promising new and exciting applications that will shape the technological landscape for years to come.


In the grand tapestry of elemental history, Iridium (Ir) stands as a rare and captivating element, weaving its story through centuries of discovery, challenges, and diverse applications. From its early recognition as a distinct metal to its integral role in modern technologies, the history of Iridium unveils a fascinating journey that spans continents and centuries. Join us as we embark on a shimmering odyssey through the history of Iridium, a metal that has quietly shaped the course of scientific exploration and industrial progress.


1. Discovery Amid Platinum Group Metals

The story of Iridium began in the early 19th century when the scientific community was immersed in the exploration of platinum group metals. In 1803, two British chemists, Smithson Tennant and William Hyde Wollaston, were examining residues left after dissolving platinum ores in aqua regia. Within this intricate matrix of metals, they discovered a new element with remarkable properties. The element's unique resistance to corrosion and high melting point set it apart, and it was duly named Iridium, derived from the Latin word "iris," meaning rainbow, in reference to the diverse colors of its compounds.


2. Challenges in Isolation and Early Use

Despite the discovery of Iridium, isolating the metal proved to be a formidable challenge. Its close association with other platinum group metals hindered the separation process. It wasn't until several decades later, in 1844, that the isolation of Iridium in its metallic form was successfully achieved by the German chemist Heinrich Rose. Early use of Iridium was limited due to its extreme rarity, but its unique properties attracted the attention of scientists and jewelers alike.


3. Iridium in Spark Plugs

The dawn of the 20th century saw Iridium making its mark in a practical and widespread application—spark plugs. The durability and high melting point of Iridium made it an ideal material for the electrodes in spark plugs. This application significantly enhanced the performance and efficiency of internal combustion engines, marking a pivotal moment in Iridium's journey from laboratory curiosities to practical industrial use.


4. Catalytic Applications

As the mid-20th century unfolded, Iridium's catalytic properties began to garner attention in the field of industrial chemistry. Iridium catalysts proved instrumental in facilitating crucial chemical reactions, particularly in processes like hydrogenation and dehydrogenation. These catalytic applications played a vital role in the synthesis of organic compounds, contributing to the production of essential chemicals and pharmaceuticals.


5. Iridium in Space Exploration

Iridium found new frontiers in the latter half of the 20th century, becoming a valuable component in space exploration. Iridium alloys, known for their resilience and resistance to corrosion, became integral in the construction of components for spacecraft and satellites. The reliability of Iridium alloys under the harsh conditions of space solidified their place in the aerospace industry.


6. Medical Imaging and Radiotherapy

Iridium's journey extended into the field of medicine with the use of the radioactive isotope Iridium-192. This isotope emits gamma rays and found application in medical imaging and radiotherapy. Iridium-192 became a crucial tool for non-destructive testing in industrial radiography and played a role in cancer treatment, showcasing Iridium's versatility in advancing healthcare technologies.


7. Niche Applications and Investments

Beyond its widespread applications, Iridium found its way into niche markets. Iridium coins, often minted in limited quantities, became sought-after items for collectors and investors appreciating the metal's rarity and intrinsic value. The beauty and scarcity of Iridium contributed to its status as a unique and coveted asset in the world of precious metals.


8. Ongoing Research and Emerging Technologies

In the 21st century, Iridium continues to be a subject of interest in ongoing research and emerging technologies. Its unique properties, including high corrosion resistance and stability, position it as a valuable material in the development of advanced materials, nanotechnology, and quantum computing. The enduring allure of Iridium in scientific exploration hints at its potential contributions to cutting-edge technologies yet to unfold.


9. Enduring Beauty in Jewelry

Iridium's history intertwines with the world of aesthetics as well. While the metal itself is too brittle for practical use in jewelry, alloys of Iridium with other metals contribute to the creation of durable and corrosion-resistant pieces. The enduring beauty of Iridium alloys enhances the longevity and aesthetic appeal of jewelry crafted for those who appreciate both durability and elegance.


10. Iridium's Legacy

As we reflect on the journey of Iridium through the annals of history, its legacy emerges as a testament to human curiosity, ingenuity, and adaptability. From its humble beginnings as a laboratory curiosity to its integral role in diverse industries, Iridium has left an indelible mark on the landscape of science, technology, and even art. As we continue to explore the frontiers of knowledge and innovation, the shimmering legacy of Iridium persists, promising new chapters in the ongoing story of this extraordinary element.

Atomic Data

Atomic Radiues, Non-bonded (A): 2.13
Electron Affinity (kJ mol-1): 150.884
Covalent Radiues (A): 1.32
Electronegativity (Pauling Scale): 2.2
Ionisation Energies (kJ mol-1) 1st 2nd 3rd 4th 5th 6th 7th 8th
865.186 - - - - - - -

Oxidation States and Isotopes

Common oxidation states 6, 4, 3, 2, 1, 0, -1
Isotope Atomic Mass Natural Abundance Half Life Mode of Decay
191Ir 190.961 37.3 - -
193Ir 192.963 62.7 - -

Supply Risk

Relative Supply Risk: 7.6
Crustal Abundance (ppm): 0.000037
Recycle Rate (%): >30
Production Conc.(%) : 60
Top 3 Producers:
1) South Africa
2) Russia
3) Zimbabwe
Top 3 Reserve Holders:
1) South Africa
2) Russia
3) USA
Substitutability: High
Political Stability of Top Producer: 44.3
Political Stability of Top Reserve Holder: 44.3

Pressure and Temperature Data

Specific Heat Capacity: 131
Shear Modulus: Unknown
Young Modulus: Unknown
Bulk Modulus: Unknown
Pressure 400k Pressure 600k Pressure 800k Pressure 1000k Pressure 1200k Pressure 1400k Pressure 1600k Pressure 1800k Pressure 2000k Pressure 2200k Pressure 2400k
- - - - - - 1.48 x 10-9 3.72 x 10-7 3.06 x 10-5 0.00112 Unknown



Welcome Dear listeners, to another episode of "Elemental Discoveries," the podcast that takes you on a captivating journey through the fascinating world of chemistry and the elements that shape our world. Today, we're diving deep into the realm of an element that holds a special place in both science and industry: Iridium.

Our exploration begins with a look back at the history of Iridium. Discovered in 1803 by the English chemist Smithson Tennant, Iridium derives its name from the Greek word "iris," meaning rainbow, due to its colorful and striking compounds. It's important to note that Iridium was discovered simultaneously with osmium, another member of the platinum group of metals.

Tennant's discovery of Iridium was a significant step in the understanding of platinum-group metals, which are known for their remarkable properties and unique chemical behaviors.

Iridium is a truly exceptional element, known for its extraordinary properties.

Iridium is the second-densest naturally occurring element, surpassed only by osmium. Its density is about 22.56 grams per cubic centimeter, making it twice as dense as lead.

Iridium boasts one of the highest melting points of all elements, with a staggering melting point of around 4,798 degrees Fahrenheit (2,643 degrees Celsius). This incredible heat resistance makes it invaluable in applications involving extreme temperatures.

Iridium is highly resistant to corrosion and oxidation, even at elevated temperatures. This exceptional property is crucial in various industries.

Iridium is known for its extreme hardness, making it useful in a variety of applications where durability is essential.

Iridium is relatively rare in the Earth's crust, with an abundance of only about 0.001 parts per million. It is often found in association with other platinum-group elements, primarily in alluvial deposits, as well as in meteorites. Interestingly, the layer of sediment marking the boundary between the Cretaceous and Paleogene periods, known as the K-T boundary, contains a higher concentration of Iridium, providing evidence of a massive asteroid impact that led to the extinction of the dinosaurs.

Extracting Iridium from its natural sources is a challenging process due to its rarity and the presence of other platinum-group elements. It typically involves a series of chemical processes to isolate and purify the metal.

The production of Iridium begins with the extraction of Iridium-containing ores, primarily from platinum mines. The ore is crushed and treated with a combination of acids to dissolve the Iridium along with other metals. Subsequent precipitation and refining steps yield high-purity Iridium metal.

Iridium may not be as commonly recognized as some other elements, but it has a wide range of essential applications across various industries:

Iridium's excellent conductivity and resistance to corrosion make it an ideal material for electrical contacts in spark plugs and other high-temperature and high-current applications.

Iridium is used in aerospace applications, particularly in the production of engine components and electrical connectors for spacecraft. Its heat resistance and durability are invaluable in the harsh conditions of space travel.

Iridium compounds serve as catalysts in various chemical reactions, including those used in the production of pharmaceuticals and fine chemicals. They enable more efficient and selective synthesis processes.

Iridium crucibles are used to melt and process high-temperature materials, such as glass and ceramics. Iridium-based thermocouples provide accurate temperature measurements in extreme conditions, such as in industrial furnaces.

Iridium wire is used in medical devices like catheters and guide wires for its biocompatibility and radiopacity, which allows for precise positioning under X-ray guidance.

Iridium alloys have historically been used in the tips of fountain pen nibs, enhancing their wear resistance and writing performance.

In conclusion, Iridium may be a lesser-known element, but its significance in science and industry cannot be overstated. From its critical role in aerospace to its use in catalysts that drive chemical reactions, Iridium continues to prove its worth in a multitude of applications.

As we continue our journey through the periodic table, let us remember that every element, no matter how obscure, contributes to the rich tapestry of human knowledge and innovation. Iridium, with its unique properties and diverse applications, is just one example of the hidden wonders that exist within the elements.

Thank you for joining us on this exploration of Iridium. If you found this episode enlightening, please subscribe, share, and leave a review. Stay tuned for more episodes as we uncover the stories behind the elements that shape our world. Until next time, keep exploring and discovering the marvels of science.