How will you distinguished between the following pairs of terms :
(i) Tetrahedral and octahedral voids
(ii) Crystal lattice and unit cell
(i) Tetrahedral voids Octahedral voids
1. It is much smaller than the size of Size is much larger then tetrahedral voids.
spheres in the packing.
2. Each tetrahedral void is surrounded Each octahedral void is surrounded by 6 spheres.
by 4 spheres. Hence, coordination no. Hence, its coordination no. is 6.
(ii) A regular arrangement of the constituent particles of a crystal in a three dimensional space is called crystal lattice.
The smallest three dimensional portion of a complete crystal lattice, which when repeated over and again in different directions produces the complete crystal lattice is called the unit cell.