Alright so
The "Fe" is just the symbol for Iron. Due to me not knowing if it is sitting above or below the baseline, but I'll assume it's below. This means that "Fe2" means there are 2 iron atoms.
And then the O3 represents 3 oxygen atoms in the compound.
And then the H2O is just the chemical formula for water, which consists of 2 hydrogen atoms and one oxygen atom.
