Here's why:

* FeF3: This part indicates the presence of iron and fluorine. The Roman numeral III in parentheses indicates that iron has a +3 oxidation state.

* 9H2O: This part indicates the presence of nine water molecules attached to the iron fluoride molecule. "Nona" means nine, and "hydrate" refers to the water molecules.

Therefore, the full name of the compound is iron(III) fluoride nonahydrate.