What is Fe_2(SO_4)_3 called?

$\text{Iron (III) sulfate}$ or $\text{ferric sulfate}$
Either name is still commonly used. Of course, it is formulated on the basis of electrical neutrality. 2 equiv $F {e}^{3 +}$, the ferric ion, and 3 equiv $S {O}_{4}^{2 -}$ give a neutral charge.