Aluminium crystallises in a cubic close-packed structure: Its metallic radius is '125 pm'. i. What is the length of the side of the unit cell? ii. How many unit cells are there in 1.00 cm^-3 of aluminium?

Explanation

i. For ccp structure, edge length,a .2 sqrt2 r=2 sqrt2 xx 125 pm=2 xx 1.414 xx 125=354 ... pm .

ii. Volume of ünit.cell .=a^3=(354 xx 10^-8 m)^2.
.therefore. No. of unit cells in .1.00 cm^3.