littchem - 20-6-2012 at 06:25
Hi! Recently I mixed warm solutions of iron(II) sulfate heptahydrate and potassium sodium tartrate tetrahydrate. The solution was a little bit cloudy
so I filtrated it and then I left the solution to crystallize. After a few days some yellow precipitate formed (but not much). After about 2 weeks
some yellowish green crystals formed. And now I have two questions:
1. What is the product of the reaction between FeSO4 and C4H4KNaO6?
2. And what are these crystals or actually are these crystals the product of the reaction from my first question?
Hexavalent - 20-6-2012 at 08:15
I think this should be in Beginnings.
What may have happened is that you formed a complex between the Fe2+ ions (actually, these were probably oxidized to Fe3+) and
the sodium potassium tartrate....transition metal ions often react with carboxylate salts in this manner, e.g. as with oxalates.
Are you ceertain that your 'solutions' that you began with had the solutes completely dissolved, and how pure were those solutes to begin with? What
concentration were your solutions? What temperature do you mean by 'warm'? Did you make the reagents yourself or buy them?
[Edited on 20-6-2012 by Hexavalent]
MR AZIDE - 20-6-2012 at 10:20
It sounds familiar to me when I mixed Iron(II) with oxalic acid, in the cold........Iron (II) Oxalate precipitated as a fine powder, but only after a
few hours, the nice lemon yellow colour.
I think a similar thing has happened when he has added tartrate to iron (ii), same sort of reaction has happened........ Iron (ii) tartrate, or like
you mention Hexa....a complex was formed.
.I you you leave it long enough, the precipitate sounds like is has has time to precipitate crystalline, become crystalline, and hence a slight
colour change. ,maybe due to particle size.
Barium hexacyanoferrate (ii) which i made years ago, does not immediately precipitate when Ba(ii) and hexacyanoferrate (ii) are mixed in cold, but on
standing small crystals, of a very nice pale yellow eventually separate after sevaral hours.....it seems sparingly soluble in water.
[Edited on 20-6-2012 by MR AZIDE]