I was putting up some waste, and accidentally got a drop of water in a waste beaker
that had contained a small amount of ferric chloride residue and a cotton ball that had collected salicylic acid during a filtration. I was shocked
to see a dark purple solution that had formed when the water came in contact with the cotton ball. Apon further investigation, a yellow powder had
formed on the cotton. When the powder was added to a beaker of water, a deep purple solution formed. I figured this was iron (iii) salicylate, which
was confirmed apon adding a few drops of ferric chloride to a solution of sodium salicylate. What astounds me, however are the the properties of this
compound. First of all I am shocked by the purple color of the solution when the powder is yellow. I believe it is because the complex is really only
stable in solution, and when dryed it seperates back into Fe(3+) and salycilate. I could be very wrong. Second of all, when even just a few drops of
strong acid are added, the solution clears up. When a base is added to this, it becomes yellow all though a few drops of strong acid will again make
it purple. If just strait base is used, the solution becomes a yellow green and a blue green precipitate apears. This can again be made clear with the
addition of a strong acid, yellow with base and again purple with acid.
I have seen both of those, but neither explain their properties.
[Edited on 23-11-18 by Abromination]
I thought the color change from yellow to purple was curious but couldn't find out what was going on however there was this pdf article you can google
if you haven't read it - maybe of interest to you but beyond my level.
Crystallization, Structure Determination and
Reticular Twinning in Iron(III) Salicylate:
Fe[(HSal)(Sal)(H2O)2]
Tidbit from the article ...
"In the course of such experiments, different complex structures and compositions have been proposed, but, to our knowledge, none of them have been
characterized by a crystal structure analysis. We therefore set out to crystallize Fe(III) salicylate and succeeded using the gel crystallization
technique. The starting salt was Fe(II) nitrate which slowly oxidized during the reaction with salicylic acid."
