Solid state

Solid State

A solid state is a form of matter which possesses rigidity and has a definite shape and definite volume. Some substances exist are solid because there is strong intermolecular force of attraction between their constituent particles and quite a low chemical energy So that the particles occupy a fixed position and closely packed. thus the main characteristics are:

• They possess rigidity.
• They have a definite shape and a definite volume. 
• They have high densities.
• They are incompressible.

Classification of solid

Crystalline solid: These are solid in which the particles are arranged in a regular pattern. e.g. NaCl, CsCl,sugar etc.

Amorphous Solid: These are solid in which the particles are not arranged in a regular pattern. e.g. Glass etc.

Type of Crystalline Solid

Ionic Solid

Ionic Solid the constituent particles are ions. these are made up of +ive and -ive charged ions. i.e. cations and anions have a strong electrostatic force of attraction between them. Each ion is surrounded by a definite number of opposite charges. Thus these solid have very high melting points. Since the ions are not free to move. So they do not conduct electricity in solid state. but they conduct electricity in molten state or their aqueous solution as ions become free to move e.g. NaCl, KCl, CsCl, ZnS, etc. they are soluble in polar solvents but insoluble in non-polar solvents. They are brittle because their stainity depends upon the geometrical patterns

Covalent (Network) Solid

The constituent particles are non-metal atoms are linked to adjacent atoms by the covalent bond in the solid is called network solid. they are gaint molecules there are main examples are Diamond, silicon carbide and Graphite. these solid are very hard and brittles because covalent bond is strong and directional in nature. thus these solids have a very high melting point. they are a poor conductor of heat and electricity.

Diamond: each carbon atom is sp3 hybridized. as the atoms are closely packed and joined together by covalent bonds. therefore, diamond are hard and have very high melting points, due to absence of ions( or free). covalent solid are poor conductors of electricity.

Graphite: Each carbon atom s Sp2 hybridized forming a hexagonal ring structure. As hexagonal layers have Vander wall's force