Answer
$XY_{2}$
$SiO_{2}$
$SnO_{2}$
$PbO_{2}$
Work Step by Step
The first step to create a formula is to exchange the valency.
Thus we get $X_{2}Y_{4}$
Then make the formula into a simple ratio.
$XY_{2}$
$X^{4+}$ is an ion probably in group-14, Carbon family.
$Y^{2-}$ is an ion probably in group-16, oxygen family.
So most likely it would be $SiO_{2}$
$SnO_{2}$
$PbO_{2}$
