Osmium (Os)

General Information

• Symbol: Os
• Atomic Number: 76
• Atomic Weight: 190.23 u
• Element Category: Transition metal
• Group: 8
• Period: 6
• Block: d-block

Physical Properties

• Appearance: Bluish-white, lustrous metallic
• Density: 22.59 g/cm³ (highest of all elements)
• Melting Point: 3033 °C (5491 °F)
• Boiling Point: 5012 °C (9054 °F)
• Phase at STP: Solid
• Electron Configuration: [Xe] 4f¹⁴ 5d⁶ 6s²
• Oxidation States: +8, +6, +4, +3, +2, +1, 0, -2

Chemical Properties

• Reactivity: Osmium is generally unreactive but can form oxides when heated. It forms a variety of compounds, especially with halogens and sulfur.
• Compounds: Forms compounds such as osmium tetroxide (OsO₄), osmium dioxide (OsO₂), and osmium chloride (OsCl₄).

Uses and Applications

• Alloys: Used to harden platinum and other alloys, especially for electrical contacts and fountain pen tips due to its hardness and durability.
• Catalysts: Employed as a catalyst in certain chemical reactions, including the Haber process for synthesizing ammonia.
• Osmium Tetroxide: Used in staining biological specimens for microscopy and in fingerprint detection.
• Jewelry and Watches: Sometimes used in high-end jewelry and watchmaking due to its density and durability.

Occurrence and Extraction

• Natural Occurrence: Found in platinum ores and as a trace element in alluvial deposits. Often found in the minerals osmiridium (an alloy of osmium and iridium) and iridosmine.
• Extraction: Extracted as a byproduct of nickel and copper mining. The extraction process involves isolating osmium from other platinum group metals through chemical processes.

Isotopes

• Stable Isotopes: Osmium has seven stable isotopes, including Osmium-184, Osmium-187, Osmium-188, Osmium-189, Osmium-190, and Osmium-192.
• Radioactive Isotopes: Osmium-186 is radioactive but has a very long half-life and is used primarily in scientific research.

Safety and Handling

• Hazards: Osmium itself is not highly toxic, but osmium tetroxide (OsO₄) is highly toxic and volatile. It can cause severe damage to the eyes, skin, and respiratory system.
• Precautions: Handle osmium tetroxide with extreme care, using appropriate protective equipment and working in a well-ventilated area or fume hood.

History

• Discovery: Discovered by Smithson Tennant in 1803.
• Name Origin: Named from the Greek word “osme,” meaning smell, due to the strong odor of its volatile oxide, osmium tetroxide.

Additional Facts

• Crystal Structure: Hexagonal close-packed (hcp)
• Magnetic Properties: Paramagnetic
• Thermal Conductivity: Moderate, about 87.6 W/m·K
• Electrical Resistivity: About 81 nΩ·m at room temperature

Summary

Osmium is a dense, hard, bluish-white transition metal known for its high melting point and resistance to wear. It is used in various high-durability applications, including alloys, catalysts, and certain industrial processes. Found primarily in platinum ores, osmium is extracted as a byproduct of nickel and copper mining. Osmium tetroxide, a volatile and highly toxic compound, requires careful handling.

40 Question and Answer Pairs About Osmium

1. What is the atomic number of Osmium?

   • 76

2. What is the symbol for Osmium?

   • Os

3. What is the atomic weight of Osmium?

   • 190.23 u

4. In which group of the periodic table is Osmium found?

   • Group 8

5. What period is Osmium in?

   • Period 6

6. What block does Osmium belong to?

   • d-block

7. What is the melting point of Osmium?

   • 3033 °C (5491 °F)

8. What is the boiling point of Osmium?

   • 5012 °C (9054 °F)

9. What is the density of Osmium?

   • 22.59 g/cm³

10. What is the electron configuration of Osmium?

    • [Xe] 4f¹⁴ 5d⁶ 6s²

11. What are the common oxidation states of Osmium?

    • +8, +6, +4, +3, +2, +1, 0, -2

12. What is the appearance of Osmium?

    • Bluish-white, lustrous metallic

13. Is Osmium reactive with air?

    • Generally unreactive, but forms oxides when heated.

14. Name a compound of Osmium.

    • Osmium tetroxide (OsO₄)

15. What is a common use of Osmium in alloys?

    • Used to harden platinum and other alloys.

16. How is Osmium used in catalysis?

    • Employed in chemical reactions like the Haber process for synthesizing ammonia.

17. What role does Osmium tetroxide play in microscopy?

    • Used for staining biological specimens.

18. How is Osmium used in jewelry?

    • Used in high-end jewelry and watchmaking.

19. What application does Osmium have in electrical contacts?

    • Used due to its hardness and durability.

20. Name a mineral that contains Osmium.

    • Osmiridium

21. How is Osmium extracted from ores?

    • As a byproduct of nickel and copper mining through chemical processes.

22. What is the most stable isotope of Osmium?

    • Osmium-192

23. Name a radioactive isotope of Osmium used in research.

    • Osmium-186

24. What safety hazard is associated with Osmium tetroxide?

    • It is highly toxic and volatile.

25. Who discovered Osmium?

    • Smithson Tennant

26. Where does the name Osmium come from?

    • From the Greek word “osme,” meaning smell.

27. What is the crystal structure of Osmium?

    • Hexagonal close-packed (hcp)

28. Is Osmium paramagnetic or diamagnetic?

    • Paramagnetic

29. What is the thermal conductivity of Osmium?

    • About 87.6 W/m·K

30. What is the electrical resistivity of Osmium at room temperature?

    • About 81 nΩ·m

31. What is the primary oxidation state of Osmium?

    • +8

32. Is Osmium found as a free element in nature?

    • No, it is found in minerals like osmiridium.

33. What is the common name of Osmium tetroxide?

    • OsO₄

34. What is a major application of Osmium dioxide (OsO₂)?

    • Used in certain industrial catalysts.

35. How does Osmium benefit electrical contacts?

    • Provides hardness and wear resistance.

36. What is the boiling point of Osmium in Kelvin?

    • 5285 K

37. What group does Osmium belong to in the periodic table?

    • Transition metals

38. What is the natural abundance of Osmium-192?

    • About 41%

39. Can Osmium be used in high-temperature applications?

    • Yes, due to its high melting point and stability.

40. What is the key property that makes Osmium valuable in microscopy?

    • Its use in osmium tetroxide for staining biological specimens.