Which of the following is NOT a crystalline allotrope of carbon?

Correct option is C

The correct answer is (c) Coke.
Explanation:

• Coke is an amorphous form of carbon and not a crystalline allotrope. It is a residue obtained during the destructive distillation of coal.
  
• Crystalline allotropes of carbon include:
  
• Diamond: A three-dimensional network structure, extremely hard.
  
• Graphite: A layered structure with excellent electrical conductivity.
  
• Fullerene: Molecules of carbon atoms arranged in a spherical or tubular shape, such as C60.

Information Booster

• Crystalline Allotropes of Carbon:Diamond, Graphite, and Fullerenes.
  
• Amorphous Forms of Carbon:Coke, coal, charcoal, and lampblack.
  
• Properties of Coke: High carbon content, used as a fuel and reducing agent in metallurgical processes.
  
• Fullerenes: Discovered in 1985; consist of carbon atoms arranged in closed shells.