Octet rule and its limitations
Chemical Bonding (Basics) · Chemistry
Study notes
SF₆ exists but OF₆ does not. Explain using octet limitations. Step 1: S in SF₆ has 12 electrons around it (6 bonds) — expanded octet. Step 2: Sulphur (period 3) has empty 3d orbitals to accommodate extra electrons. Step 3: Oxygen (period 2) has NO d orbitals — cannot expand beyond 8. Step 4: Hence OF₆ is impossible; max is OF₂. Expansion needs d orbitals — only period 3+ elements.