Please dont use any chatgpt source.Assuming that like ions do not touch in either the NaCl or $CsCl$ structures, calculate the

relative packing efficiencies of both structures. Verify the result for the limit where the sizes

of the cations and anions become the same.

For zinc blende $(ZnS)$ and cristobalite $(Si{O}_2),$ estimate their lattice parameters and packing

fractions in terms of $r_{+}$and $r_{-(radii\text{f}\text{o}\text{r}\text{c}\text{a}\text{t}\text{i}\text{o}\text{n}\text{a}\text{n}\text{d}\text{a}\text{n}\text{i}\text{o}\text{n}\text{,}\text{r}\text{e}\text{s}\text{p}\text{e}\text{c}\text{t}\text{i}\text{v}\text{e}\text{l}\text{y}).}$