The correct name of FeCl₂·4H₂O is iron(II) chloride tetrahydrate.
• Must use Stock system because Fe is a transition metal and can have more than one charge
• 2Cl⁻ needs 1Fe²⁺ to balance charge, ∴ iron(II)
• Cl⁻ is chloride (no multiplying prefix for binary ionic compounds)
• 4 = “tetra” + water = “hydrate” → tetrahydrate
Put it all together and you get iron(II) chloride tetrahydrate (three words)
