How do you name ionic compounds with transition metals?
You write the name as
name of cation(charge in Roman numerals) + name of anion
In general, the name of an ionic compound is
name of cation + name of anion
Cations in of non-transition metals have the same name as the metal (e.g., sodium, magnesium, aluminum).
Transition metals form cations with more than one charge. To distinguish these cations, we add the charge as a capital Roman numeral in parentheses.
Fe²⁺ is iron(II); Fe³⁺ is iron(III); Cu⁺ is copper(I); Cu²⁺ is copper(II)
Note that there are no spaces between the letters and the parentheses.
MgSO₄ = Mg²⁺ + SO₄²⁻ magnesium sulfate, but
FeSO₄ = Fe²⁺ + SO₄²⁻ iron(II) sulfate
Al₂(SO₄)₃ = Al³⁺ + SO₄²⁻ aluminum sulfate but
Fe₂(SO₄)₃ = Fe³⁺ + SO₄²⁻ iron(III) sulfate