Ferroin sulfate Although I started this article I now regret that I did not assign the full formula for a real salt vs an ion Since the sulfate is the most common salt of ferroin I suggest that we either 1 move the article to Iron II tris phenanthroline sulfate seems cumbersome or 2 tweak the current article to focus mainly on the sulfate the same CAS but this way we can discuss solubility structure prep while acknowledging that the properties in soln are independent of the anion