Ask a Teacher

Search



in fcc lattice,a unit cell is shared by how many unit cells a)2 b)4 c)6 d)8
ANS:B
A face-centred cubic (fcc) unit cell contains atoms at all the corners and
at the centre of all the faces of the cube.Each atom located at the face-centre is shared between two adjacent unit cells and only 1/2 of each atom belongs to a unit cell.Thus, in a face-centred cubic
(fcc) unit cell:
(i) 8 corners atoms × 1/8
atom per unit cell = 8 × 1/8= 1 atom
(ii) 6 face-centred atoms ×1/2atom per unit cell
= 6 ×1/2
= 3 atoms
? Total number of atoms per unit cell= 4 atoms


comments powered by Disqus