- #1
dadon
- 11
- 1
Hey All..
I'm having some problems trying to understand the tetrahedral and octahedral sites in face centered cubic (fcc) and body centered cubic (bcc). It is hard to visualise the structures in 3D..
I wanted to know how to find out the positions per unit cell for the tetrahedral and octahedral in both fcc and bcc..
For the tetraheral
fcc = 8 tetrahedron per unit cell
bcc = 12 tetrahedron per unit cell
The bcc is worked out (6*4)/2 = 12
For the octrahedral
fcc = 4 octrahedron per unit cell
bcc = 6 octrahedron per unit cell
The fcc is worked out (12/4)+1 = 4
The bcc is worked out (12/4)+(6/2) = 6
Although I have the soultions I'm still confused how they are worked out to the above answers..I have attached a picture.. hope someone can help
Thank you
I'm having some problems trying to understand the tetrahedral and octahedral sites in face centered cubic (fcc) and body centered cubic (bcc). It is hard to visualise the structures in 3D..
I wanted to know how to find out the positions per unit cell for the tetrahedral and octahedral in both fcc and bcc..
For the tetraheral
fcc = 8 tetrahedron per unit cell
bcc = 12 tetrahedron per unit cell
The bcc is worked out (6*4)/2 = 12
For the octrahedral
fcc = 4 octrahedron per unit cell
bcc = 6 octrahedron per unit cell
The fcc is worked out (12/4)+1 = 4
The bcc is worked out (12/4)+(6/2) = 6
Although I have the soultions I'm still confused how they are worked out to the above answers..I have attached a picture.. hope someone can help
Thank you