What state is SnCl4 at room temperature?

Both contain Sn in 4 + oxidation state. As the charge on the cation is very high, the nature of these compounds will be more covalent. They tend to exist in molecular form rather than in ionic form.

So the attractions between the molecules is weak vander Waal's forces of attractions. These attractions become stronger with more force in the molecular wt.

As the mol. wt of SnI4 is greater than SnCl4, the attractions in SnI4 will be stronger. Hence SnI4 is solid and SnCl4 is a liquid at room temp.