Calculate the formula of a compound if its structure has sodium atoms at the cube centres, oxygen atoms at the cube edges while tungsten (W) atoms are located at the corners of the unit cell. Also, write the type of the lattice represented by this compound. 

From the given data, it is clear that the lattice type of the compound is simple cubic. 

No. of Na atoms at the cube centre

$=1\times 1=1$

No. of 0-atoms at the cube edges

$=12\text{ edges }\times \frac{1}{4}=3\text{ edges }$

No. of W-atoms at the corners of unit cell

3                 30         $=8\times \frac{1}{8}=1$.

$\therefore$ Formula of compound

$={\mathrm{Na}}_1{\mathrm{O}}_3{\mathrm{W}}_1$or ${\mathrm{NaWO}}_3$

So, the correct answer is (2).