Why is [Fe(SCN)(H_2O)_5]^2+ red Why is [FeF_6]^3- colourless Why is [Fe/H_2O]_6 light yellow Kill me please
When white light strikes [Fe(SCN)(H_2O)_5]^2+, only red is passed through. When white light strikes [FeF_6]^3-, all is passed through. When white light strikes [Fe/H_2O]_6, only yellow is passed through.
I did find the reason for the fluoride - there is no possible excitation without spin reversion, making absorption require radiation of higher energy. For the Aqua complex I found the reasoning that the yellowish part is actually a multi-core complex bridged by oxo-ligands, reducing the effect of the Laporte ban. I am currently struggling to find another source for that though, does anyone know where to look? Darklord, I was looking for the chemical reasons why the absorption is working that way, not what is absorbed, because thats pretty easy Also, your explanation is not entirely correct; it appears red because green is absorbed, not because all colors but red are.
Still not a bad answer for only going through high school physics. If only green was absorbed, wouldn't it be a mix of all colors except green? I was also guessing that these were solutions and not solids. *Edit* I realize Red is opposite green on the color wheel, which would mean that red would be the strongest, but all other colors would be present.
Well you see, [FeF_6]^3- is colorless because the pigment gnomes that work with this particular fluid are on strike due to poor health benefits and low job satisfaction. Thus, they outright refuse to provide this fluid with color until they reach a settlement with the CEO of Technicolor Industries.
Actually, the Aqua complex is yellow because the corresponding hydroxide has some CT sheanigans going ... At least I think its CT? Can't things between d->d and CT be somewhat more easy to discern
You can suppress the colour with H_2SO_4. Not with HCl or HOAc though, which odd for HCl, though rather expected for HOAc. Whenever I don't hate chemistry I love it.
