Lecture 13 - Molecular orbitals in solids

Flashcards covering key concepts and definitions related to molecular orbitals in solids, including topics like conductivity, band structures, and semiconductor types.

What are core electrons?

Electrons in core orbitals that are unaffected by neighbouring atomic nuclei.

What is the Pauli exclusion principle regarding atomic and molecular orbitals?

A maximum of 2 electrons can occupy an atomic or molecular orbital.

What is the bond order formula?

Bond order = 1/2 (No. of bonding electrons - No. of antibonding electrons)

What is the valence band?

The band of occupied orbitals in network solids.

What is the conduction band?

The band of unoccupied orbitals in network solids.

What is a band gap?

The minimum energy required to promote an electron from the valence band to the conduction band.

What are the characteristics of graphite?

Black & opaque, highly conducting, low density, soft solid.

What are the characteristics of diamond?

Transparent, insulator, high density, hardest solid.

How do metals conduct electricity?

Metals have overlapping valence and conduction bands with no band gap.

What is an intrinsic semiconductor?

A semiconductor with a small band gap, allowing electrons to be promoted to the conduction band.

What is n-type doping?

Substituting an element with more electrons to create extra negative charge carriers.

What is p-type doping?

Substituting an element with fewer electrons to generate holes in the valence band.

How can solar cells be generated?

By combining an intrinsic semiconductor with both p-type and n-type extrinsic conductors.