Classification of crystalline solids

Crystalline solids

 

 

Molecular solids

 

Non-polar

Polar

Hydrogen-bonded

Soft

Soft

Hard

Insulator of electricity

Insulator of electricity

Insulator of electricity

Very low melting point

Low melting point

Low melting point

Intermolecular forces - Dispersion or London forces

Intermolecular forces - Dipole - dipole interaction

Intermolecular forces - Hydrogen bonding

Example – Ar , CCl4 , H2 , CO2

Example –HCl , SO2

Example –H2O

 

Parameters

Ionic solids

Metallic solids

Covalent solids

Constituent particles

Ions

Positive ions in the sea of delocalized electrons

Atoms

Attractive forces

Electrostatic

Metallic bonding

Covalent bonding

Physical Nature

Hard but brittle

Hard but malleable and ductile

Hard (diamond)

Soft (Graphite )

Electrical conductivity

Insulators in solid state but conductors in molten state and in aqueous solutions

Conductors in solid state as well as in molten state

Insulators except graphite

Melting point

High

Fairly High

Very high