Aluminium metal has a density of `2.72 g cm^(-3)` and crystallizes in a cubic lattice with an edge of `404` pm. Which is//are correct?

Options

A. It forms an fcc unit cell.
B. It forms a bcc unit cell.
C. Its coordination number is `8`.
D. Its coordination number is `12`.

Answer

A, D

Explanation

Use any relation:
`rho=(Z_(eff)xxAw)/(N_(A)xxa^(3))` or `rho=(Z_(eff)xxAwxx1.67xx10^(-24)g)/(a^(3))`
`:. 2.72 g cm^(-3) = (Z_(eff)xxAwxx1.67xx10^(-24)g)/((404xx10^(-10))^(3)cm^(3))`
`:. Z_(eff) approx = 4`
`a. Z_(eff) = 4`, means fcc structure.
d. `CN` of fcc structure `= 12`