How many atoms are contained in a body centered cubic cell?

Question

How many atoms are contained in a body centered cubic cell?

Answer 1

Think of it this way:

 

You have 1 atom at the center, and 1 atom at each of 8 corners.  But each corner atom is shared by 8 adjacent unit cells, so you can say there is 1/8 of an atom at each corner of a given unit cell.  The combination of 1 atom in the center and 1/8 of an atom at each of the 8 corners makes the total for a single unit cell come out to

 

1 + 8*(1/8) = 1 + 1 = 2 atoms