Question

which is the proper chemical formula for iron(iii) sulfide?
fes
irs3
fe2s3
fe3s

Explanation:

Iron(III) has a +3 charge ($Fe^{3 + }$), and sulfide ion has a - 2 charge ($S^{2-}$). To form a neutral compound, we need 2 iron(III) ions and 3 sulfide ions according to the criss - cross rule for writing ionic compound formulas.

Answer:

C. $Fe_2S_3$