crystalline structures

What does SC stand for?

Simple Cubic

Atoms in SC unit cell

1 atom

How are atoms arranged in SC?

At the corners of the cube

Coordination number of SC

6

Radius formula for SC

r = a/2

Packing efficiency of SC

52.4%

What does BCC stand for?

Body-Centred Cubic

Atoms in BCC unit cell

2 atoms

Where is the extra atom in BCC?

In the centre of the cube

Coordination number of BCC

8

Radius formula for BCC

r = (√3/4)a

Where do atoms touch in BCC?

Along the body diagonal

Packing efficiency of BCC

68.0%

What does FCC stand for?

Face-Centred Cubic

Atoms in FCC unit cell

4 atoms

Where are the extra atoms in FCC?

On each face

Coordination number of FCC

12

Radius formula for FCC

r = (√2/4)a

Where do atoms touch in FCC?

Along the face diagonal

Packing efficiency of FCC

74.0%

What does HCP stand for?

Hexagonal Close Packed

Atoms in HCP unit cell

6 atoms

Coordination number of HCP

12

Packing efficiency of HCP

74%

What is the packing efficiency formula?

PE = (n × Vparticle / Vunit cell) × 100

Volume of a particle

(4/3)πr³

Volume of unit cell

a³