Aluminium metal forms a cubic close-packed crystal structure. Its atomic radius is 125xx10^(-12)m. (a) Calculate the length of the side of the unit cell. (b) How many such unit cells are there in 1.00 m^3 of aluminium ?

Aluminium metal forms a cubic close-packed crystal structure. Its atom

1.	Aluminium metal forms a cubic close-packed crystal structure. Its atomic radius is 125xx10^(-12)m. (a) Calculate the length of the side of the unit cell. (b) How many such unit cells are there in 1.00 m^3 of aluminium ?
Answer» Solution :ccp=fcc. For fcc, `r=a/(2sqrt2)` or `a=2sqrt2r=2xx1.414xx125xx10^(-2) m =354xx10^(-12) m`=354 PM VOLUME of one unit CELL =`(354xx10^(-12)m)^3=4.436xx10^(-29) m^3` `therefore` No. of unit cell in 1 `m^3=1/(4.436xx10^(-29))=2.25xx10^28`