What are differences between #"Mohr's salt"#, and #"green vitriol"#?

Question

Luna Chen · Accepted Answer

Well, #"green vitriol"# is #Fe(SO)_4#, an iron(II) salt.........

And #"Mohr's salt"# is #(NH_4)_2[Fe(SO_4)_2] *6H_2O#. Therefore, they have different coordination geometries and are different formulations in the solid state. In solution, however, for both species, we LIKELY have #[Fe(OH_2)_6]^(2+)# as the dominant iron species in solution. The sulfate and ammonium counterions are along for the ride. There is possibly some literature on this, which is likely informed by #"UV-vis spectrometry"#.

Wyatt Atkins · Answer

undefined Mohr's salt, or ammonium iron(II) sulfate, has the chemical formula (NH4)2Fe(SO4)2·6H2O, while green vitriol, or ferrous sulfate, has the chemical formula FeSO4·7H2O. They differ in their chemical compositions and structures, as well as in their uses. Mohr's salt is a double salt containing ammonium ions, iron(II) ions, and sulfate ions, while green vitriol is a simple salt containing iron(II) ions and sulfate ions. They also have different properties and applications, with Mohr's salt often used in analytical chemistry and green vitriol used in various industrial processes, including water treatment and as a supplement in animal feed.