Number of atoms in unit cell:Primitive cubic unit cell. In this type of unit cell the constituent particles occupy the 8 corners. So the total no. of atoms in one unit cell.Body centered unit cell in this type of unit cell the constituent particles occupy the 8 corners and body center. So, the total no. of atoms in one unit cell face centered unit cell in this type of unit cell, the constituent particles occupy the 8 corners and 6 faces.One dimensional packing let us consider the constituent particles as hard sphere which help us in explaining the packing.There is only one way of arraying the sphere and it is in contact with 2 other spheres. So its co-ordination.Two dimensional packing a Square close packing two dimensional packing can be arranged in two different ways.AA range the second layer of spheres in contact with first layer such that each sphere is in contact with four other spheres. (Sphere is aligned horizontally as well as vertically). So the co-ordination number is 4. If the first row is of 'A' type and second row is exactly the same as first then this type of arrangement is called 'AAA' type of arrangement or square packing.Hexagonal close packing:Arrange the second layer of spheres in contact with first layer such that each sphere is in contact with 6 other spheres (second row spheres fit in the depression of first row spheres). So the co-ordination number is 6. If the first row is of 'A' type and second row is of 'B' type then this type of packing is called 'ABAB' type of packing or Hexagonal packing. The empty space is less when compared to square packing.Three dimensional close packing simple cubic lattice Ex: - Polonium these are generated by placing two dimensional layers on one above the other.This type of packing is obtained by placing layers exactly on the top of first layer. Such that each sphere is in contact with 6 spheres four from the same layer one from the top layer and one from the bottom layer. This type of arrangement is called 'AAA' type of arrangement. The total space occupied by the spheres is 52% and the remaining space is void.The co-ordination number is Ex: - Polonium.

ที่มา : http://www.7active.in

ลิงค์ : http://youtu.be/y0c5WILbzQw

อัพโหลดโดย : 7activestudio