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Sciencemadness Discussion Board » Fundamentals » Chemistry in General » Unexplained crystals produced in the synthesis of potassium trisoxalatoferrate(III)

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PYRIDINEyade

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posted on 27-2-2023 at 02:18

Unexplained crystals produced in the synthesis of potassium trisoxalatoferrate(III)

Greetings,

I recently synthesized potassium trisoxalatoferrate(III) by reacting an aqueous oxalic acid solution with potassium hydroxide and adding an aqueous iron(III) chloride solution to it.
Then, a very small portion of the crystals had a blue-green color. What is this?
I have synthesized potassium trisoxalatoferrate(III) many times, but this is the first time I have seen it.

Regards,

PYRIDINEyade

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posted on 27-2-2023 at 02:25

Always, as you can see in this picture, all the crystals are yellow-green.

Texium

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posted on 21-9-2023 at 16:16

What was your source of iron(III) chloride, and was it the same stuff you used the previous times? If not, perhaps this time it was contaminated with another metal like copper or nickel.

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clearly_not_atara

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posted on 21-9-2023 at 17:23

Trisoxalatochromate is reportedly very dark blue.

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PYRIDINEyade

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posted on 22-9-2023 at 15:15

@Texium
As a source of iron(III) chloride, I used a etching liquid. I used the same etching liquid before.
https://www.amazon.co.jp/dp/B0020VFJ8K

After I started this thread, I asked my friend and he said that isotopes are the most likely source. Other possibilities are the crystal grains are finer and thus appear optically bluish, or that some Fe(+3) may be reduced to Fe(+2) since oxalic acid is a reducing agent.

SnailsAttack

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posted on 22-9-2023 at 18:32

Quote: Originally posted by PYRIDINEyade

After I started this thread, I asked my friend and he said that isotopes are the most likely source.

I don't think that's a thing

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violet sin

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posted on 22-9-2023 at 19:23

Straight, fresh, clean etchant? Or, could it possibly have copper in there? Seems to me an impurity of some sort is the likely cause. Good luck.

Side note, I agree with SnailsAttack.
I doubt any kind of isotopic discrepancy would alter the color perceptibly, if at all. Pure gess, not looked into.

Sciencemadness Discussion Board » Fundamentals » Chemistry in General » Unexplained crystals produced in the synthesis of potassium trisoxalatoferrate(III)