Chemistry - Solid State Question with Solution | TestHub

For a face-centered cubic (fcc) unit cell, the relationship between the edge length $a$ and the atomic radius $r$ is given by:

$a=2\sqrt{2}r$

Given $r=139\text{ pm}$:

$a=2\times 1.414\times 139\text{ pm}$

$a=393.1\text{ pm}$

Converting picometers to centimeters:

$a=393.1\times 10^{-10}\text{ cm}$

$a=3.93\times 10^{-8}\text{ cm}$

Answer: $3.93\times 10^{-8}\mathrm{cm}$