01 What is Sodium Chloride?
Table salt. An ionic compound forming a 3D crystal lattice where each Na⁺ is surrounded by 6 Cl⁻ and vice versa. High melting point (801°C) because ionic bonds throughout the lattice all need to be broken to melt.
02 Why It Matters
Essential for life - Na⁺ and Cl⁻ ions maintain cell membrane potential, nerve conduction, and fluid balance. Historically so valuable it was used as currency (root of the word "salary"). Ocean water is ~3.5% NaCl.
03 Structure and Bonding
Shape: Face-centred cubic crystal lattice
Bonds: Ionic bonds (electrostatic attraction between Na⁺ and Cl⁻)
Polarity: Ionic (not molecular) - The bonding creates a complex charge distribution across the structure.
The entire ocean contains ~5 × 10¹⁹ kg of NaCl. If it were all extracted and spread over Earth's land surface, it would form a layer about 150 metres thick.