In this topic, we have to discuss the types of crystalline solids. Crystalline solids are classified into four categories as follows:
1. Molecular solids: Solids whose constituent particles are molecules are called molecular solids.
Molecular solids are of three types:
I. Non-polar molecular solids: A solid in which the constituent particles are held by weak dispersion forces or London forces are called non-polar molecular solids.
Ex: H2, O2, N2, Noble gases like He, Ne, Ar, Kr etc
II. Polar molecular solids: A solid in which the constituent particles are held by dipole-dipole forces is called a polar solid.
Ex: HCl, NH3, SO2 etc
III. Hydrogen bonded molecular solids: A solid in which the constituent particles are held by Hydrogen bond is called a hydrogen bonded molecular solids.
Ex: Ice, HF etc
2. Covalent or network solids: A solid in which the constituent particles form a huge network of very strong covalent bonds is called a covalent or network solid.
Ex: Diamond, Graphite, Silica, Silicon Carbide etc.
3. Ionic solids: A solid whose constituent particles are ions is called an ionic solid.
Ex: NaCl, MgCl2 etc
4. Metallic solids: A solid whose constituent particles are atoms of a metal is called a metallic solid.
Ex: Fe, Cu, Zn etc.