The correct option is C-60 Fullerene.
Explanation
Carbon exhibits allotropy, meaning it exists in different physical forms with the same chemical properties. The major crystalline allotropes of carbon include diamond, graphite, and fullerenes. Fullerenes are large, cage-like spheroidal molecules made entirely of carbon.
Option Analysis
- C-60 Fullerene is correct: C-60 Fullerene, also known as Buckminsterfullerene, consists of 60 carbon atoms arranged in a series of interlocking hexagons and pentagons. Its structure is a truncated icosahedron, which is geometrically identical to a standard football (soccer ball) or a geodesic dome. It was named after the architect R. Buckminster Fuller, who popularized geodesic domes.
- C-70 Fullerene is incorrect: C-70 Fullerene is another stable fullerene but has a structure resembling a rugby ball rather than a spherical football.
- Diamond is incorrect: Diamond has a rigid, three-dimensional network where each carbon atom is bonded to four others in a tetrahedral arrangement. It does not form a cage-like structure.
- Graphite is incorrect: Graphite consists of carbon atoms arranged in planar hexagonal sheets layered on top of one another. It does not form a closed dome structure.
Key Takeaway
Buckminsterfullerene (C-60) is the carbon allotrope with a cage-like structure containing 20 hexagons and 12 pentagons, resembling a geodesic dome or a football.