Rhenium (Re)

General Information

• Symbol: Re
• Atomic Number: 75
• Atomic Weight: 186.207 u
• Element Category: Transition metal
• Group: 7
• Period: 6
• Block: d-block

Physical Properties

• Appearance: Silvery-gray metallic
• Density: 21.02 g/cm³
• Melting Point: 3186 °C (5767 °F)
• Boiling Point: 5596 °C (10105 °F)
• Phase at STP: Solid
• Electron Configuration: [Xe] 4f¹⁴ 5d⁵ 6s²
• Oxidation States: +7 (most common), +6, +4, +2, -1

Chemical Properties

• Reactivity: Rhenium is relatively inert and resistant to corrosion and oxidation. It reacts with halogens and sulfur but does not react with hydrochloric acid or other common acids.
• Compounds: Forms compounds such as rhenium heptoxide (Re₂O₇), rhenium trichloride (ReCl₃), and perrhenic acid (HReO₄).

Uses and Applications

• Superalloys: Used in superalloys for jet engine parts and gas turbine blades due to its high melting point and strength.
• Catalysts: Employed as a catalyst in the chemical industry, particularly in the production of high-octane gasoline and in hydrogenation reactions.
• Electrical Contacts: Used in electrical contacts and thermocouples due to its good electrical conductivity and resistance to wear.
• Medical: Investigated for use in radioactive isotopes for cancer treatment.
• Filaments: Used in filaments for mass spectrometers and ion gauges.

Occurrence and Extraction

• Natural Occurrence: Found in trace amounts in minerals such as molybdenite (MoS₂) and is often extracted as a byproduct of molybdenum and copper mining.
• Extraction: Extracted through roasting molybdenum concentrates to form rhenium heptoxide, which is then reduced with hydrogen to produce rhenium metal.

Isotopes

• Stable Isotopes: Rhenium-185 and Rhenium-187
• Radioactive Isotopes: Rhenium-186 and Rhenium-188, used in medical applications and scientific research.

Safety and Handling

• Hazards: Rhenium is generally considered to be of low toxicity, but its compounds should be handled with care as some may be hazardous.
• Precautions: Handle with appropriate protective equipment to avoid inhalation or ingestion of dust or fumes.

History

• Discovery: Discovered by Walter Noddack, Ida Tacke, and Otto Berg in 1925.
• Name Origin: Named after the Latin name for the Rhine River, “Rhenus.”

Additional Facts

• Crystal Structure: Hexagonal close-packed (hcp)
• Magnetic Properties: Paramagnetic
• Thermal Conductivity: Moderate, about 48 W/m·K
• Electrical Resistivity: About 193 nΩ·m at room temperature

Summary

Rhenium is a transition metal known for its high melting point, density, and strength. It is used in superalloys for jet engines, as a catalyst in the chemical industry, and in electrical contacts. Found primarily in molybdenite, rhenium is extracted as a byproduct of molybdenum and copper mining. Despite its useful properties, rhenium is rare and requires careful handling.

40 Question and Answer Pairs About Rhenium

1. What is the atomic number of Rhenium?

   • 75

2. What is the symbol for Rhenium?

   • Re

3. What is the atomic weight of Rhenium?

   • 186.207 u

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

   • Group 7

5. What period is Rhenium in?

   • Period 6

6. What block does Rhenium belong to?

   • d-block

7. What is the melting point of Rhenium?

   • 3186 °C (5767 °F)

8. What is the boiling point of Rhenium?

   • 5596 °C (10105 °F)

9. What is the density of Rhenium?

   • 21.02 g/cm³

10. What is the electron configuration of Rhenium?

    • [Xe] 4f¹⁴ 5d⁵ 6s²

11. What are the common oxidation states of Rhenium?

    • +7, +6, +4, +2, -1

12. What is the appearance of Rhenium?

    • Silvery-gray metallic

13. Is Rhenium reactive with air?

    • No, it is relatively inert and resistant to corrosion and oxidation.

14. Name a compound of Rhenium.

    • Rhenium heptoxide (Re₂O₇)

15. What is a common use of Rhenium in superalloys?

    • Used in jet engine parts and gas turbine blades.

16. How is Rhenium used as a catalyst?

    • In the production of high-octane gasoline and in hydrogenation reactions.

17. What role does Rhenium play in electrical contacts?

    • Used for its good electrical conductivity and resistance to wear.

18. How is Rhenium used in medical applications?

    • Investigated for use in radioactive isotopes for cancer treatment.

19. What application does Rhenium have in filaments?

    • Used in filaments for mass spectrometers and ion gauges.

20. Name a mineral that contains Rhenium.

    • Molybdenite (MoS₂)

21. How is Rhenium extracted from ores?

    • By roasting molybdenum concentrates to form rhenium heptoxide, then reducing it with hydrogen.

22. What is the most stable isotope of Rhenium?

    • Rhenium-185

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

    • Rhenium-186

24. What safety hazard is associated with Rhenium compounds?

    • Some compounds may be hazardous if inhaled or ingested.

25. Who discovered Rhenium?

    • Walter Noddack, Ida Tacke, and Otto Berg

26. Where does the name Rhenium come from?

    • From the Latin name for the Rhine River, “Rhenus.”

27. What is the crystal structure of Rhenium?

    • Hexagonal close-packed (hcp)

28. Is Rhenium paramagnetic or diamagnetic?

    • Paramagnetic

29. What is the thermal conductivity of Rhenium?

    • About 48 W/m·K

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

    • About 193 nΩ·m

31. What is the primary oxidation state of Rhenium?

    • +7

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

    • No, it is found in minerals like molybdenite.

33. What is the common name of Rhenium heptoxide?

    • Re₂O₇

34. What is a major application of Rhenium trichloride (ReCl₃)?

    • Used in chemical synthesis.

35. How does Rhenium benefit jet engines?

    • Provides high melting point and strength in superalloys.

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

    • 5869 K

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

    • Transition metals

38. What is the natural abundance of Rhenium-185?

    • About 37.4%

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

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

40. What is the key property that makes Rhenium valuable in electrical contacts?

    • Its good electrical conductivity and resistance to wear.