Octet Rule Exceptions

Boron

stable with only 6 electrons (3 bonds)

Beryllium

stable with only 4 electrons (2 bonds)

Phosphorus

stable with 10 electrons (5 bonds)

Sulfur

stable with 12 electrons (6 bonds)

Always

less than 8 electrons

Not always

Expanded Valence - involves the d orbitals as weel as s + p