Cobalt: Element Overview

Basic Information

• Symbol: Co
• Atomic Number: 27
• Atomic Weight: 58.933194 u
• Element Category: Transition metal
• Group: 9
• Period: 4

Physical Properties

• Phase at Room Temperature: Solid
• Melting Point: 1495 °C (2723 °F)
• Boiling Point: 2927 °C (5301 °F)
• Density: 8.90 g/cm³ at 20 °C
• Color: Lustrous, silver-gray metal
• Crystal Structure: Hexagonal close-packed (hcp) at room temperature, face-centered cubic (fcc) at higher temperatures

Chemical Properties

• Electronegativity: 1.88 (Pauling scale)
• Ionization Energies:
  • First: 760.4 kJ/mol
  • Second: 1648 kJ/mol
  • Third: 3232 kJ/mol
• Oxidation States: +2, +3 (most common), +1, +4
• Reactivity: Reacts slowly with oxygen and water; forms protective oxide layer.

Isotopes

• Stable Isotopes: Cobalt has one stable isotope: Co-59.
• Radioisotopes: The most notable radioisotope is Co-60, which is used in medical and industrial applications.

Occurrence and Production

• Natural Abundance: Cobalt is the 32nd most abundant element in the Earth’s crust.
• Sources: Found in minerals such as cobaltite (CoAsS), erythrite (Co₃(AsO₄)₂·8H₂O), and as a byproduct of nickel and copper mining.
• Production: Extracted by flotation processes followed by pyrometallurgical or hydrometallurgical techniques.

Uses and Applications

• Alloys: Used to make superalloys for jet engines and gas turbines due to its high-temperature strength and corrosion resistance.
• Batteries: Essential component in lithium-ion batteries.
• Magnets: Used in the production of strong permanent magnets like alnico and samarium-cobalt magnets.
• Catalysts: Used as a catalyst in the petroleum and chemical industries.
• Medical: Used in the production of orthopedic implants and in radiotherapy for cancer treatment (Co-60).

Safety and Precautions

• Reactivity: Relatively non-reactive but can react with acids.
• Handling: Cobalt dust and fumes should be handled with care to avoid inhalation and skin contact.
• Toxicity: Cobalt compounds can be toxic if ingested or inhaled in large quantities; prolonged exposure can lead to respiratory issues and skin sensitization.

Biological Role

• Essential Element: Cobalt is essential for humans as a component of vitamin B12 (cobalamin).
• Health: Required in trace amounts for red blood cell production and neurological function.

Historical Background

• Discovery: Known to ancient civilizations but identified as an element by Georg Brandt in 1735.
• Naming: Named after the German word “kobalt” or “kobold,” meaning goblin or evil spirit, due to the troublesome nature of its ores to miners.

Interesting Facts

• Cobalt Blue: A bright blue pigment made from cobalt compounds, historically significant in art and ceramics.
• Radiation Source: Cobalt-60 is a significant source of gamma rays used in medical treatments and sterilization.
• Space Exploration: Used in materials for spacecraft due to its durability and resistance to space environments.

Summary

Cobalt is a versatile transition metal known for its high-temperature strength, corrosion resistance, and essential role in biological systems. It is primarily extracted as a byproduct of nickel and copper mining and is used in superalloys, batteries, magnets, and medical applications. Discovered in the 18th century, cobalt continues to be a critical material in modern technology, from aerospace engineering to healthcare.

Questions and Answers about Cobalt:

1. Q: What is the chemical symbol for Cobalt?

   • A: Co

2. Q: What is the atomic number of Cobalt?

   • A: 27

3. Q: What type of element is Cobalt?

   • A: Transition metal

4. Q: What is the atomic weight of Cobalt?

   • A: 58.933194 u

5. Q: What group is Cobalt in?

   • A: Group 9

6. Q: What period is Cobalt in?

   • A: Period 4

7. Q: What is the phase of Cobalt at room temperature?

   • A: Solid

8. Q: What is the melting point of Cobalt?

   • A: 1495 °C (2723 °F)

9. Q: What is the boiling point of Cobalt?

   • A: 2927 °C (5301 °F)

10. Q: What is the density of Cobalt at 20 °C?

    • A: 8.90 g/cm³

11. Q: What is the color of Cobalt metal?

    • A: Lustrous, silver-gray

12. Q: What is the crystal structure of Cobalt?

    • A: Hexagonal close-packed (hcp) at room temperature, face-centered cubic (fcc) at higher temperatures

13. Q: What is the electronegativity of Cobalt?

    • A: 1.88 (Pauling scale)

14. Q: What is the first ionization energy of Cobalt?

    • A: 760.4 kJ/mol

15. Q: How many stable isotopes does Cobalt have?

    • A: One (Co-59)

16. Q: What is the most notable radioisotope of Cobalt?

    • A: Co-60

17. Q: How is Cobalt commercially produced?

    • A: Extracted by flotation processes followed by pyrometallurgical or hydrometallurgical techniques

18. Q: What is the natural abundance of Cobalt in the Earth’s crust?

    • A: 32nd most abundant element

19. Q: What common minerals contain Cobalt?

    • A: Cobaltite (CoAsS), erythrite (Co₃(AsO₄)₂·8H₂O)

20. Q: What industry uses Cobalt extensively for superalloys?

    • A: Aerospace industry

21. Q: What is one use of Cobalt in the battery industry?

    • A: Essential component in lithium-ion batteries

22. Q: What role does Cobalt play in the production of magnets?

    • A: Used in the production of strong permanent magnets like alnico and samarium-cobalt magnets

23. Q: Why is Cobalt used in the chemical industry?

    • A: Used as a catalyst in various chemical reactions

24. Q: What is the biological role of Cobalt in the body?

    • A: Component of vitamin B12, essential for red blood cell production and neurological function

25. Q: Who discovered Cobalt?

    • A: Georg Brandt

26. Q: In what year was Cobalt discovered?

    • A: 1735

27. Q: What is the origin of the name “Cobalt”?

    • A: From the German word “kobalt” or “kobold,” meaning goblin or evil spirit

28. Q: What property makes Cobalt suitable for use in superalloys?

    • A: High-temperature strength and corrosion resistance

29. Q: What health hazard is associated with prolonged exposure to Cobalt dust or fumes?

    • A: Can cause respiratory issues and skin sensitization

30. Q: How should Cobalt and its compounds be handled?

    • A: With care, using appropriate protective equipment to avoid inhalation and skin contact

31. Q: What is the second ionization energy of Cobalt?

    • A: 1648 kJ/mol

32. Q: What is the third ionization energy of Cobalt?

    • A: 3232 kJ/mol

33. Q: Is Cobalt essential for plant health?

    • A: Not essential for most plants, but required by some microorganisms

34. Q: What is the significance of Cobalt in enzyme function?

    • A: Acts as a cofactor in enzymatic reactions, particularly in vitamin B12

35. Q: What is the role of Cobalt in the production of orthopedic implants?

    • A: Used due to its biocompatibility and strength

36. Q: How does Cobalt benefit the medical industry?

    • A: Used in radiotherapy for cancer treatment and in the production of medical implants

37. Q: What is Cobalt’s role in improving battery technology?

    • A: Enhances energy density and cycle life in lithium-ion batteries

38. Q: What is the use of Cobalt in pigments and dyes?

    • A: Produces bright blue pigments like cobalt blue

39. Q: How does Cobalt contribute to space exploration?

    • A: Used in materials for spacecraft due to its durability and resistance to space environments

40. Q: What color are Cobalt compounds typically?

    • A: They can exhibit a variety of colors, with cobalt blue being particularly notable