Some car paints include tiny flakes of silica, $\text{SiO}_2$. In solid $\text{SiO}_2$, the structure has: - each silicon atom attached to $x$ oxygen atoms, - each oxygen atom attached to $y$ silicon atoms, - each bond being a $z$ type bond. Which is the correct set of values for $x$, $y$ and $z$ in these statements?
- A$x = 2$, $y = 1$, covalent
- B$x = 2$, $y = 1$, ionic
- C$x = 4$, $y = 2$, covalent
- D$x = 4$, $y = 2$, ionic