There was an interesting question posed on the Sceptical Chymist last week: is the cyclization reaction that makes the chromophore of green fluorescent protein a rare event or a common one; and how do we find out?
In return for bringing that question to the attention of my biochemical friends, I have a question for the chemists.
Is Prussian Blue made from ferric chloride and potassium ferrocyanide, or ferrous chloride and potassium ferricyanide, or some unholy mixture of the two? Because I’m having a little local difficulty remembering and I’m not sure we have the right reagents in the lab to do the experiment myself. All I can recall at the moment is ‘hexacyanoferrate’ which is the product.
Before you say anything, wikipedia is self-contradictory.
Am I the only one sort of nervously wondering why Richard wants to know this? Exactly?
Prussian Blue is made of blue Prussians. I thought that was obvious.
Ah Jenny, I could tell you.
But then I’d have to drag you off to my secret laboratory buried in the mountains and perform strange and dastardly experiments on You.
Oh all right Henry, you can come too, but you must promise not to enjoy it.
err,
And I guess that’s why they call it the bruise ?
Having just annoyed the crystallographers, and finding that they didn’t have any ferrous chloride, but they did have ferric chloride and ferrous sulphate, I can now report that yellowy-green potassium ferricyanide (also known as K hexacyanoferrate) when mixed with pale blue FeII (i.e., ferrous), turns lovely Prussian blue.
Which is what I’d have thought.
Have you asked the Sceptical Chymists? or Stephen?
Well, I was hoping that NN would pingback to the post but…
Anyway, it seemed a trivial thing to trouble them for, when I could do the experiment myself.