. How will you distinguish between the following pairs of terms (i) Hexagonal close-packing and cubic close-packing


How will you distinguish between the following pairs of terms:
 
            (i) Hexagonal close-packing and cubic close-packing?
 
            (ii) Crystal lattice and unit cell?
 
            (iii) Tetrahedral void and octahedral void?
 

 

Best Answer

(i) In hexagonal close packing (hep), the spheres of the third layer are vertically above the spheres of the first layer. It means that tetrahedral voids of the second layer are covered by the spheres 'of the third layer. The AB AB AB ..... type.  
In cubic close packing (ccp), the spheres of third layer cover the octahedral voids of second layer. But the spheres of the fourth layers are aligned with those of the first layer. The pattern is ABC ABC ...... type
2
 
 

Talk to Our counsellor