It isn't.
There are no Roman numerals in it.
Fe = Iron (from Latin 'ferrum')
O = Oxygen
H = Hydrogen
3 = Arabic numeral.
Iron III hydroxide
The balanced equation for this reaction is Fe2O3 + 3 H2O = 2 Fe(OH)3.
3Fe + 4(H2O) ---> Fe3O4 + 4(H2) You really should learn this, its not that hard =D