3.10 Describe the bonding in diamond and graphite in terms of the hybrid orbital model (valence bond theory). Explain how the macroscopic properties of diamond and graphite (appearance, melting point, strength, electricity conductance, etc.) can be explained in terms of the kind of bonding that occurs in these networks.

What type of hybridization occurs in diamond?

sp³ hybridization occurs in diamond, where each carbon forms four sigma bonds with neighboring carbon atoms.

How is the bonding structure in diamond arranged?

The sp³ hybrid orbitals form a tetrahedral arrangement, creating a three-dimensional network of covalent bonds.

What are the macroscopic properties of diamond?

• Appearance: Transparent, as there are no free electrons to absorb visible light.

• Melting Point: Very high, due to strong covalent bonds in the network.

• Strength: Extremely hard, as carbon atoms are strongly bonded in a rigid lattice.

• Electricity Conductance: Does not conduct electricity, as there are no free electrons.

What type of hybridization occurs in graphite?

sp² hybridization occurs in graphite, where each carbon forms three sigma bonds with neighboring carbon atoms.

How does bonding in graphite differ from diamond?

In graphite, the remaining unhybridized p-orbital forms pi bonds, creating delocalized electrons across layers.

What is the structure of graphite?

Layers of carbon atoms are arranged in hexagonal rings and are held together by weak van der Waals forces, allowing the layers to slide over each other.

What are the macroscopic properties of graphite?

• Appearance: Opaque and shiny due to delocalized electrons reflecting light.

• Melting Point: High, but layers can break down under extreme heat due to weak forces between them.

• Strength: Soft and slippery as the layers can slide over one another.

• Electricity Conductance: Conducts electricity because delocalized electrons can move freely within layers.

How does the structure of diamond differ from graphite?

• Diamond: Three-dimensional network of strong covalent bonds.

• Graphite: Layered structure with weak forces between layers and delocalized electrons.

How do bonding and hybridization influence the properties of diamond and graphite?

• Diamond: sp³ hybridized bonds form a strong network, making it hard, non-conductive, and high-melting.

• Graphite: sp² hybridized bonds with delocalized electrons allow conductivity, softness, and the ability to conduct electricity.