SOLID ELECTROLYTE

Base on its electrical properties, material could be divide into:
1. Conductor
2. Semiconductor
3. Isolator

The conductor or conducting materials could be classified into:
1. Ionic conductor
2. electronic conductor
3. mixed ionic-electronic conductor

Meanwhile based on its material's characteristic, the ionic conductor could be classified as:
1. Crystalline electrolyte
2. Glassy electrolyte
3. Polymer electrolyte

CRYSTALLINE ELECTROLYTE

Here are some points we need to learn to discuss the nature of solids:
1. the chemical bonding in solids
2. lattice energy of ionic crystals
3. structure of crystals
4. determination of crystal structure
5. imperfection in solid
6. atom movements in solid

CHEMICAL BONDING IN SOLID:
the principles types of chemical bonding are:
1. ionic
2. covalent
3. metallic
4. van der walls


IONIC BONDS are formed when one atom on the interacting pair 
is quite electropositive and the other electronegative , so that 

the first atom loses a valence electron to the second one, the the 

attractive force is due to the electrostatic attraction of two 

opppsitely charged ions (Hannay, 1967)

COVALENT BONDING is formed due to a sharing of electrons,supplied by one or both of the atoms.

Figure . examples of crystal lattice with ionic bond and covalent bond

METALLIC BONDING. The bonding in a metal must be thought of in terms of 
all the atoms of the solid taken collectively, with the valence electrons from all the atoms belonging to the crystal as a whole.

“free electron’ theory by DRUDE described metal as composed of a lattice of positive metal ions embedded in an electron ‘gas’ permeating the whole crystal, which is held by resulting electrostatic interaction between the ions and electrons



VAN DER WALLS. Van der Walls forces can also provide the cohesive forces which bind together a solid. This binding energy in solid is quite weak. Examples: some low melting organic crystals.

LATTICE ENERGY OF IONIC CRYSTAL

Two principal kinds of force determine ionic crystal structures:

a) Electrostatic force of attraction and repulsion, which is give by Coulomb’s law
b) Short-range repulsive forces which are important when atoms or ions are so close and their electron clouds begin to overlap (West, A.,1999)

The Lattice Energy of ionic solid is defined as the enthalpy of formation of the ionic compound from gaseous ions. 
It may also defined as the energy required to completely  It may also defined as the energy required to completely separate one mole of a solid ionic compound into gaseous ionic constituents.

Enthalpy change of ionic crystal formation, ∆Hf , or symbolyzed as U in West (1999) can be calculated as:

THE CRYSTAL STRUCTURE

Crystal lattice is network of points with regularly repeating spacings and parallel arrangements of the points.

The Baravais Lattice