aluminium crystallises in a ccp structure and its metallic radius is 125 pm calculate the edge length of the cell and also find the number of unit cell in 1cm3 of aluminum
Answers
Answer:
For the cubic close–packed structure Let a is the edge of the cube and r is the radius of atom
Given that r = 125 pm
a = 2√2 r
Plug the value of r we get
= 2 x 1.414 x125 pm
= 354 pm (approximately)
Volume of one unit cell = side3 = (354 pm)3
1 pm = 10–10 cm
= (354 x 10–10 cm)3
= (3.54 x 10–8 cm)3
= 44.36 x 10–24 cm3
= 4.4 × 10−23 cm3
Total number of unit cells in 1.00 cm3
= total volume / size of each cell
= (1.00cm3)/( 4.4 × 10−23 cm3)
= 2.27 × 1022 unit cell