[Xe] 4f145d66s2
2, 8, 18, 32, 14, 2
3033°C, 5491°F, 3306 K
5008°C, 9046°F, 5281 K
Smithson Tennant
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Uses and Properties

Image Explanation

The alloy known as osmiridium, composed mainly of Osmium, or iridosmine, where iridium takes precedence, is employed for fountain pen nibs. The paramount quality sought in a fountain pen is its smooth writing experience, hinging on the proper balance of resilience and smoothness in the nib. With remarkable resistance to acid and wear, pen tips crafted from osmium alloy deliver a consistent, smooth writing sensation that endures for years on end.


A shiny, silver metal that resists corrosion. It is the densest of all the elements and is twice as dense as lead.


Osmium: Unveiling the Hidden Marvel in Modern Applications

In the realm of precious metals, Osmium (Os) stands as a hidden gem, often overshadowed by its more illustrious counterparts. However, this dense and rare element boasts unique properties that have found niche applications across various industries. From the realms of fine writing instruments to cutting-edge science, Osmium plays a pivotal role in shaping the world around us. Join us as we unveil the multifaceted uses of Osmium, a marvel hidden in plain sight.


1. Fountain Pen Nibs

Osmium takes center stage in the world of fine writing instruments, particularly in the crafting of fountain pen nibs. When alloyed with other metals, such as iridium, it forms osmiridium or iridosmine, depending on the predominant metal. These alloys contribute to the durability and resilience of pen nibs, ensuring a smooth and consistent writing experience. The ability of osmium alloys to withstand the rigors of daily use makes them a cherished choice for discerning pen enthusiasts.


2. Industrial Catalysts

Osmium compounds serve as catalysts in various industrial processes, contributing to the synthesis of organic compounds. Its catalytic properties play a crucial role in promoting chemical reactions, enhancing the efficiency of processes such as hydrogenation and dehydrogenation in the production of chemicals and pharmaceuticals. Osmium's catalytic prowess makes it a valuable asset in advancing industrial chemistry.


3. Microscopy Staining

In the field of life sciences, osmium tetroxide, a compound of osmium, finds application as a staining agent in electron microscopy. The unique electron density of osmium tetroxide allows it to interact with biological specimens, enhancing their visibility under electron microscopes. This staining technique is instrumental in studying cellular structures and advancing our understanding of microscopic life.


4. Jewelry Alloys

While osmium itself is not commonly used in jewelry due to its brittleness, its alloys play a role in the world of jewelry crafting. Alloys of osmium with other metals contribute to the creation of durable and corrosion-resistant jewelry. These alloys, often combined with precious metals like gold and platinum, enhance the longevity and aesthetic appeal of jewelry pieces.


5. Electrical Contacts

Osmium alloys, owing to their hardness and resistance to wear, are utilized in the production of electrical contacts. These contacts play a vital role in electrical switches, relays, and connectors, where durability and reliability are paramount. The ability of osmium alloys to maintain their integrity under repeated electrical contact ensures the longevity and efficiency of electrical components.


6. X-ray and Gamma Ray Shielding

Osmium, with its high density, serves as an effective material for shielding against X-rays and gamma rays. In medical imaging and radiation therapy, osmium-based materials are employed to protect individuals and equipment from harmful radiation. The dense nature of osmium makes it an ideal choice for ensuring the safety of both patients and healthcare professionals in radiological applications.


7. Osmium Clocks

Osmium has found its way into the intricate world of horology, where its unique properties contribute to the precision of atomic clocks. Isotopes of osmium, such as osmium-187, play a role in the calibration of these highly accurate timekeeping devices. The stability and predictability of osmium isotopes make them valuable tools in maintaining the accuracy of atomic clocks, which are essential for modern timekeeping standards.


8. Scientific Research

Osmium's dense nature and unique properties make it a valuable tool in scientific research, particularly in studies involving high-pressure experiments. Osmium is used as an anvil material in diamond anvil cells, devices that create extreme pressures for investigating the properties of materials under such conditions. The role of osmium in these experiments contributes to advancements in materials science and high-pressure physics.


9. Aerospace Applications

Osmium alloys, known for their hardness and resistance to corrosion, find applications in the aerospace industry. Components made from osmium alloys contribute to the structural integrity and durability of aircraft and spacecraft. The ability of osmium alloys to withstand harsh environmental conditions and mechanical stress positions them as reliable materials in aerospace engineering.


10. Emerging Technologies

As technology advances, the unique properties of osmium continue to capture the attention of researchers and innovators. Ongoing exploration includes the potential use of osmium in emerging technologies such as quantum computing and advanced materials science. The dense and stable nature of osmium positions it as a material of interest in the quest for cutting-edge solutions to complex technological challenges.



Osmium, often overlooked in the world of precious metals, emerges as a versatile and invaluable element with applications spanning from the elegance of fine writing instruments to the precision of atomic clocks. Its unique properties, from catalytic prowess to shielding against radiation, contribute to advancements in diverse industries. As we continue to unlock the mysteries of science and technology, the hidden marvel of osmium stands ready to reveal even more applications, shaping the future of innovation in ways we are only beginning to explore.


In the vast tapestry of elemental history, Osmium (Os) emerges as a hidden protagonist, its journey marked by discovery, fascination, and a myriad of applications across diverse fields. From its initial recognition as a rare and dense metal to its pivotal role in modern technologies, the history of Osmium unveils a captivating tale of scientific exploration and industrial evolution. Join us as we trace the elemental odyssey of Osmium, a journey that spans centuries and continues to shape the world around us.


1. Discovery Amid Platinum

The story of Osmium begins in the late 18th century when chemists were delving into the mysteries of platinum group metals. In 1803, the English chemist Smithson Tennant, working alongside his colleague William Hyde Wollaston, identified and isolated a dense and rare metal from platinum ore. This newly discovered element exhibited unique properties, distinguishing it from its fellow platinum group members. Tennant named it "Osmium," derived from the Greek word "osme," meaning odor, owing to the distinctive, unpleasant smell of its volatile oxide.


2. Early Challenges in Isolation

The isolation of Osmium proved to be a formidable challenge for early chemists due to its close association with other platinum group metals. Its high melting point and tendency to form volatile oxides posed obstacles to the extraction process. It wasn't until the mid-19th century that advancements in metallurgical techniques allowed for more successful isolation and characterization of Osmium.


3. The Brittle Beauty in Alloys

While Osmium itself proved to be too brittle for practical applications, its alloys showcased remarkable properties. Alloyed with other metals, Osmium found a role in enhancing the durability and resilience of materials. The creation of osmiridium, an alloy with iridium, became particularly significant, as it was utilized in the crafting of durable and corrosion-resistant pen nibs.


4. Osmium and the Precious Metal Trade

Throughout the 19th and early 20th centuries, Osmium found itself entwined with the precious metal trade, albeit in a somewhat understated manner. Its rarity and unique characteristics contributed to its allure among collectors and investors, adding a layer of intrigue to the already fascinating world of precious metals.


5. Osmium in the Atomic Clock

As the 20th century unfolded, Osmium found itself playing a crucial role in the pursuit of precision timekeeping. Isotopes of Osmium, particularly Osmium-187, became instrumental in the calibration of atomic clocks. The stability of Osmium isotopes provided a reliable reference for the accurate measurement of time, contributing to advancements in the field of horology.


6. Catalyst of Innovation

Osmium's catalytic properties became a focal point of scientific exploration, especially in the realm of industrial chemistry. Osmium compounds were employed as catalysts, promoting essential chemical reactions in the synthesis of organic compounds. This catalytic prowess played a pivotal role in advancing the field of industrial chemistry, contributing to the production of chemicals and pharmaceuticals.


7. Microscopy and the World Unseen

In the world of microscopy, Osmium emerged as a vital tool for revealing the hidden intricacies of biological specimens. Osmium tetroxide, a compound of Osmium, served as a staining agent in electron microscopy. This staining technique became indispensable for studying cellular structures, opening a window into the microscopic world and advancing our understanding of life at the cellular level.


8. Aerospace and Beyond

Osmium's resilience and resistance to corrosion positioned it as a valuable material in aerospace applications. Components made from Osmium alloys contributed to the structural integrity and durability of aircraft and spacecraft. The ability of Osmium to withstand harsh environmental conditions and mechanical stress made it a reliable choice in the ever-evolving landscape of aerospace engineering.


9. Shielding Against the Unseen

With its high density, Osmium became a preferred material for shielding against X-rays and gamma rays. In medical imaging and radiation therapy, Osmium-based materials played a crucial role in protecting individuals and equipment from harmful radiation. The dense nature of Osmium became an asset in ensuring the safety of both patients and healthcare professionals in radiological applications.


10. Ongoing Exploration and Future Frontiers

As we stand on the precipice of the 21st century, the journey of Osmium continues. Ongoing exploration into its unique properties sparks interest in emerging technologies such as quantum computing and advanced materials science. The dense and stable nature of Osmium positions it as a material of interest in the ongoing quest for innovative solutions to complex technological challenges.



Osmium, once a hidden marvel in the world of elements, has evolved from its discovery in the 18th century to become a player in the realms of science, technology, and industry. Its journey, marked by challenges and triumphs, reflects the ever-expanding landscape of human knowledge and innovation. As we peer into the future, the story of Osmium continues, promising new chapters of discovery and applications yet to unfold, shaping the course of science and industry for generations to come.

Atomic Data

Atomic Radiues, Non-bonded (A): 2.16
Electron Affinity (kJ mol-1): 106.1
Covalent Radiues (A): 1.36
Electronegativity (Pauling Scale): 2.2
Ionisation Energies (kJ mol-1) 1st 2nd 3rd 4th 5th 6th 7th 8th
814.165 - - - - - - -

Oxidation States and Isotopes

Common oxidation states 8, 6, 4, 3, 2, 0, -2
Isotope Atomic Mass Natural Abundance Half Life Mode of Decay
184Os 183.952 0.02 - -
186Os 185.954 1.59 2 x 1015 y α
187Os 186.956 1.96 - -
188Os 187.956 13.24 - -
189Os 188.958 16.15 - -
190Os 189.958 26.26 - -
192Os 191.961 40.78 - -

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: 130
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
- - - - - - - 1.85 x 10-10 3.46 x 10-8 2.49 x 10-6 Unknown



Welcome Dear listeners, to another enlightening episode of "Talking About Elements," the podcast that uncovers the mysteries and marvels of the chemical world. I'm your guide, and today, we're embarking on a journey to discover the extraordinary element known as Osmium.

Our exploration begins with a glimpse into the history of Osmium. Discovered in 1803 by the English chemist Smithson Tennant, Osmium derives its name from the Greek word "osme," meaning odor, due to the pungent, chlorine-like odor of Osmium tetroxide, one of its compounds.

Tennant, in collaboration with William Hyde Wollaston, isolated Osmium from crude platinum ore. This discovery marked a significant milestone in the exploration of platinum-group metals and their unique properties.

Osmium is a remarkable element in many respects. It ranks as one of the densest naturally occurring elements, with a density about twice that of lead. This extreme density gives Osmium the title of the "heaviest element" in the periodic table. Its atomic number is 76, and its symbol is Os.

One of Osmium's most distinctive properties is its extraordinarily high melting point, standing at approximately 5,491 degrees Fahrenheit (3,033 degrees Celsius). This exceptional heat resistance makes it invaluable in applications that involve extreme temperatures.

Let's delve into the occurrence and extraction of Osmium. While Osmium is relatively rare in the Earth's crust, it is typically found in association with other platinum-group elements, particularly in platinum and nickel ores. The primary source of Osmium is the mineral osmiridium, which contains varying amounts of both Osmium and iridium.

Extracting Osmium is a complex process that involves multiple steps, including crushing the ore, dissolving it in aqua regia, and then precipitating Osmium as Osmium tetroxide. The purification process is intricate due to the similar properties of Osmium and other platinum-group metals.

The production of Osmium involves several stages of refining and purification to obtain high-purity Osmium metal. Once extracted as Osmium tetroxide, it can be converted into a more usable form, such as powder or pellets. This high-purity Osmium serves as a foundation for various applications.

Now, let's explore the myriad of applications where Osmium proves its worth.

Osmium alloys were historically used in the tips of fountain pen nibs. Its hardness and resistance to wear made it an ideal material for ensuring a smooth and consistent writing experience.

Osmium is employed in high-quality electrical contacts for its resistance to oxidation and durability. These contacts are found in a wide range of electrical devices and switches.

Osmium forms alloys with other metals, such as platinum and iridium, to create materials with unique properties. These alloys are used in the production of thermocouples, where accurate temperature measurements are required.

Despite its toxic nature, Osmium tetroxide is used in laboratories for fixing biological samples and staining tissues for electron microscopy. It plays a crucial role in the field of life sciences.

Osmium compounds serve as catalysts in various chemical reactions, including asymmetric synthesis, where it helps produce specific chiral molecules essential in pharmaceuticals and agrochemicals.

Osmium complexes are under investigation for their potential as anti-tumor agents in cancer therapy. Their ability to interact with DNA and proteins shows promise in the development of novel cancer treatments.

Osmium is used in the aerospace industry, particularly in the production of high-temperature, heat-resistant parts for aircraft and rockets.

In conclusion, Osmium, with its intriguing history, exceptional properties, and diverse applications, may not be the most well-known element, but it certainly has its place in the world of science and technology. From its role in electrical contacts to its potential in cancer treatment, Osmium continues to be a valuable contributor to various fields.

As we continue our exploration of the chemical world, remember that every element, no matter how obscure, has its unique story to tell and its own set of contributions to human knowledge and progress. So, stay curious, and keep delving into the mysteries of the elements that surround us.

Thank you for joining us on this journey through the world of Osmium. If you enjoyed this episode, please subscribe, share, and leave a review. And don't forget to tune in next time as we uncover more fascinating stories about the elements that shape our universe. Until then, keep exploring and discovering the wonders of science.


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