- CH.PHYSICS

# Bravais Space Lattice

**Bravais Space Lattice:**

**Bravais Space Lattice:**

## Bravais showed that there are 14 ways of arranging points in space lattice called the Bravais lattice. In case of a cubic system, there are 3 Bravais lattice.

## Those are 1) Simple Cubic or Primitive Cubic

## 2) Face Centered Cubic (**fcc**)

## 3) Body Centered Cubic (**bcc**)

__1.Simple Cubic:__

__1.Simple Cubic:__

** **There** **is one lattice point at each of eight corners of the unit cell. The share of each lattice point to the cubic lattice = 1/8.

## Number of lattice points in unit cell = 1/8 x 8 = 1

## i.e. there is only one lattice point per unit cell.

__2. Face Centred Cubic:__

__2. Face Centred Cubic:__

## There is one lattice point at each of the eight corners and one lattice point at the centers of each of the six faces of the cubic cell.

## Total number of corners lattice points in unit cell 8 x (1/8) = 1

## Total number of face centered lattice points in unit cell = 6 x ½ = 3.

## Total number of lattice points concerned with unit cell = 1+3=4.

**3.** __Body Centered Cubic:__

__Body Centered Cubic:__

## There is one lattice point at each of the eight corners and one lattice point at the center of each cell.

## Total number of corner lattice points per unit cell 8 x (1/8) = 1.

## Total number of body centered lattice points per unit cell = 1.

## Total number of lattice points concerned with unit cell = 1 + 1 = 2.

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