ferrocene
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Thanks for this.
Who is the book's author and when was it written?
If my memory serves me correctly, Mellor stated that K2FeO5 was obtained by heating Fe2O3, KOH and a large excess of KNO3. A green melt is obtained, which becomes a green solid on cooling. When I tried it, I certainly obtained a green melt, but it became white when cooled. Sadly, I can't remember anything else.
I had doubts then about the existence of iron (VIII). If it doesn't exist, then I wonder why not?
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Does anyone have information about the chemistry of iron in oxidation state VIII ? (The chemistry of iron (VI) is well documented)
Mellor’s Treatise on Inorganic Chemistry devotes only a couple of paragraphs to the preparation of potassium perferrate K2FeO5 and iron tetraoxide FeO4. I remember as a teenager trying out the experiments described, but didn’t obtain the same results.
I have googled extensively but found nothing of help.
(How do I convert a number to sub-script?)
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Iron (VIII)
in Inorganic Chemistry
Posted
Thanks for this, Woelen - interesting points you raise, quite a few of them new to me. The evidence certainly suggests that Fe (VIII) does not exist. However, I remember reading (quite some time ago) why KBrO4 and the perbromates could not possibly exist - but that didn't stop them from existing. I also noted a detailed description of OsF8 - and subsequently a report saying it definitely does not exist.
I am curious then as to what might be happening when Fe2O3, KOH and a large excess of KNO3 are heated. (Unfortunately, I didn't copy the equation that Mellor gave - but this was many years ago) I remember clearly that a dark green melt was produced, that it turned white when it cooled and solidified (contrary to what Mellor said). I cannot think of any iron compound which would behave in such a way under those conditions. There are a number of iron compounds which are white, but I can't think of any which would fit this particular bill.
Unfortunately, I'm not in a position to try this experiment again.