Question

Calculate the number of atoms or particalper unit cell of 1)simple unit cell and 2)BCC,3)FCC

Answer 1

1)constitute particles are at only centre Number of atom=number of corners *contribution at corner =8*1/8=1 2)fcc:particles are at centre and each face Number of atom =number of corners *contribution at corner +number of face center *contribution at each face =8*1/8 +6*1/2=1+3=4 3)bcc:particles are at corner and at centre Number of atom =number of corners *contribution at corner +number of body Centre *contribution of body center =8 *1 /8 +1*1=1+1=2