Linked Questions

30 votes
9 answers
11k views

What are oxidation states used for?

When I took high school chemistry many years ago, considerable effort was spent on teaching us to compute oxidation states of atoms in various compounds, following a set of rules that looked somewhat ...
hmakholm left over Monica's user avatar
25 votes
3 answers
12k views

Why is there a difference in the colours of K₂Cr₂O₇ and K₂CrO₄?

In both the compounds the oxidation state of chromium is +6 so why is there a difference in the colours of their aqueous solutions? $\ce{K2Cr2O7}$ is red-yellow and $\ce{K2CrO4}$ is bright yellow. I ...
Agyey Arya's user avatar
9 votes
3 answers
5k views

Can any atom donate more than 1 lone pair as a coordinate bond to the same metal?

This would mean the formation of a σ and one or two π bonds, all coordinate. I haven't heard of this happening, like a fluorine anion or water with two lone pairs on oxygen will donate ...
Charles's user avatar
  • 2,725
18 votes
2 answers
4k views

Color of chromate and permanganate

I've heard quite a few times that the chromate and permanganate have a $d^3s$ configuration. Also, their colors arise due to a rapid switching of electrons between the oxygen and metal atoms. I don't ...
ManishEarth's user avatar
  • 15.3k
13 votes
2 answers
12k views

Why do octahedral metal ligand complexes have greater splitting than tetrahedral complexes?

Octahedral complexes have greater splitting in the d orbitals. Is it because octahedral complexes have more atoms and thus more interactions?
CognisMantis's user avatar
  • 1,648
9 votes
1 answer
7k views

Why are compounds of V5+ and Cr6+ colored? [duplicate]

As far as my knowledge goes, transition metal complex ions show a color due to a transfer of electrons between the levels of split $\mathrm d$-orbitals. In the case of $\ce{V^5+}$ and $\ce{Cr^6+}$ ...
GenericIBstudent's user avatar
5 votes
1 answer
1k views

How are the π bonds arranged in Osmium Tetroxide?

The structure of $\ce{OsO4}$ has puzzled me greatly for a while. I know that it has a tetrahedral geometry. I am quite piqued at the thought of how the $π$ bonds were arranged in the molecule. My ...
Pritt says Reinstate Monica's user avatar
5 votes
1 answer
3k views

How potassium ferrocyanide is coloured?

The colour of a complex compound is due to unpaired electrons. As per crystal field theory, $\ce{K4[Fe(CN)6]}$ has no unpaired electrons so it has to be colourless. But then why is it coloured?
JM97's user avatar
  • 3,477
4 votes
1 answer
1k views

Why do better π-acceptor ligands cause smaller Δ(T) d-orbital splitting?

Consider a formazanate ligand. Then imagine an electron-withdrawing group added to it. I expect a small σ-donating effect, and good π-accepting properties. My supervisor tells me that an ...
Timon van der Berg's user avatar
3 votes
1 answer
2k views

How does complex ion differ from ligand complex?

As I understand, in terms of "colouring", ligand complex cause a transition metal cation centre's d-shell to split, allowing the electrons in that region to absorb specific frequencies of light, and ...
user289661's user avatar
1 vote
1 answer
507 views

Why is chromate coloured but tungstate colourless?

I have to try and work this out using the tetrahedral molecular orbital diagram for $\ce{[WO4]^2-}$ but I am confused as both are $\mathrm d^0$ right?
Fariha's user avatar
  • 19
2 votes
0 answers
497 views

Difference in color between the chromate and permanganate ions

As the title states, I'm wondering why the $\ce{[CrO4]^2-}$ and $\ce{[MnO4]-}$ ions display different colors in solution. Both of the metal ions have a $\mathrm{d}^0$ electron configuration, have the ...
OddFunction's user avatar
1 vote
0 answers
93 views

How is Mn+7 in the Permanganate ion considered as momentarily reduced to +6 in LMCT? [duplicate]

I saw this passage on a book and it says that Ligand to Metal Charge Transfer (LMCT) overpowers d-d transitions thus the permanganate ion has an intense purple color. However, it was mentioned that ...
Kent de los Reyes's user avatar
1 vote
0 answers
429 views

Color of potassium permanganate and potassium dichromate [duplicate]

In $\ce{KMnO4}$, the Oxidation state of $\ce{Mn}$ is +7, which results in an electronic configuration as $\ce{[Ar] 4s^0 3d^0}$ In $\ce{K2Cr2O7}$,the Oxidation state of $\ce{Cr}$ is +6, which results ...
Ritwik Das's user avatar
  • 2,209
0 votes
0 answers
65 views

Why is potassium permanganate coloured? [duplicate]

$\ce{Mn}$ in $\ce{KMnO4}$ is in $+7$ oxidation state, has no d electrons so d-d transition is not possible. Then, how is $\ce{KMnO4}$ coloured?
Vishnu JK's user avatar
  • 1,264