# Chemistry doubt!

I Have got a problem.

The complex [FeF6]3- Does not have any color while [CoF6]3- Has a color.

Why? .

From theory in both the complexes d-d transition is possible

Note by Prakhar Bindal
4 years, 7 months ago

This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.

When posting on Brilliant:

• Use the emojis to react to an explanation, whether you're congratulating a job well done , or just really confused .
• Ask specific questions about the challenge or the steps in somebody's explanation. Well-posed questions can add a lot to the discussion, but posting "I don't understand!" doesn't help anyone.
• Try to contribute something new to the discussion, whether it is an extension, generalization or other idea related to the challenge.
• Stay on topic — we're all here to learn more about math and science, not to hear about your favorite get-rich-quick scheme or current world events.

MarkdownAppears as
*italics* or _italics_ italics
**bold** or __bold__ bold
- bulleted- list
• bulleted
• list
1. numbered2. list
1. numbered
2. list
Note: you must add a full line of space before and after lists for them to show up correctly
paragraph 1paragraph 2

paragraph 1

paragraph 2

[example link](https://brilliant.org)example link
> This is a quote
This is a quote
    # I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
# I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
MathAppears as
Remember to wrap math in $$ ... $$ or $ ... $ to ensure proper formatting.
2 \times 3 $2 \times 3$
2^{34} $2^{34}$
a_{i-1} $a_{i-1}$
\frac{2}{3} $\frac{2}{3}$
\sqrt{2} $\sqrt{2}$
\sum_{i=1}^3 $\sum_{i=1}^3$
\sin \theta $\sin \theta$
\boxed{123} $\boxed{123}$

Sort by:

let me give my explanation too ....High spin Fe3+ is likely with a weak field ligand like F-so this is a high spin d5 ion and no d→d transitions are possible from the 6 S ground state because there are no other sextet states possible. In the case of Co3+, this is a high spin d6 ion and the 4 D ground state is split into 4 Eg and 4 T2g states by the Oh crystal field. The only spin allowed transition will be between these states

- 4 years, 7 months ago

i do not know how to write sub-script or superscript !

- 4 years, 7 months ago

d-d transition in [FeF6]3- are spin only and quite weak making it almost colorless. however in [CoF6]3- d-d transition from t2g to eg falls under visible region giving it a consistent blue color.

- 4 years, 7 months ago

Yep that can be explained. but..

We mostly see colors by charge transfer and dd transition. we never see that the transitions are quite weak or so. but yeah i know it must be an exceptional case.

And neverthless thanks for answering and BTW how much are you getting in the AITS?

- 4 years, 7 months ago

Well. This one didn't go well. No ideas why i performed so bad. What's your rank ?

- 4 years, 7 months ago

what about you? And whats highest rank at your centre

- 4 years, 7 months ago

tune mujhe tag nahi kiya ! :(

- 4 years, 7 months ago

bhul gya tha :P

- 4 years, 7 months ago

K, let it go . i know i am stupid ! by the way best of luck for NSEP !

- 4 years, 7 months ago

Thanks and you aren't stupid!

- 4 years, 7 months ago

exceptional case !!! Despite of five unpaired electrons the complex is coulourless. It is explained in terms of extra stability of half filled configuration due to which energy involved in electronic transiition is having shorter wavelength then the visible spectrum.

- 4 years, 7 months ago

sorry for mass tagging

- 4 years, 7 months ago

Abhi coordination chal raha hai

- 4 years, 7 months ago

Friday tak khatam hoga, And maybe this will be studied in d block

- 4 years, 7 months ago

K. go on!

- 4 years, 7 months ago