Copper has a face`-` centred cubic structure with a unit`-` cell edge length of `3.61Å`. What is the size of the largest atom which could fit into the intersectices of the copper lattice without distorting if ?

Answer

`0.53Å `

Explanation

`r_("octahedral") = 0.414 R`
For FCC `4R = sqrt2a`
`R = (sqrt2a)/(4)`
`r = (0.414 sqrt2 a)/(4) = (0.414 sqrt2 xx 3.61)/(4) = 0.53Å `