Types of bonds

By symmetry	Sigma (σ) Pi (π) Delta (δ) Phi (φ)
By multiplicity	1 (single) 2 (double) 3 (triple) 4 (quadruple) 5 (quintuple) 6 (sextuple)
By spin	Triplet Singlet Exchange-coupled

Concepts	Hybrid orbital Resonance Lewis structure
Constituent units	Covalent bond Lone pair

Concepts	Molecular orbital LCAO MO diagram
Constituent units	Bonding MO Non-bonding MO Antibonding MO