Question

Crystal Field Theory (high spin and low spin) can help me clarify??

Answer 1

i am having a hunch that it must be related to Cr3+ being d3, does anyone knows why this anomally happens??

Answer 2

CN\(^-\) is a strong field ligand, therefore it would generate a higher field splitting as compared to Cl\(^-\).

Answer 3

@abb0t yup CN- is a strong field ligand, thus is should be low spin right? I understood that d3 cannot have both high and low spins, therefore it depends on the ligands. But i dont understand why CrCN6]3- is high spin

Answer 4

this is the answer sheet, i dont understand why a strong ligad should have a high spin

Answer 5

where did u get that information? any link?

Answer 6

This is due to sigma/ pi- bonding properties. This can best be expained using molecular orbital theory. Look at the M.O diagram for cyanide and look particularly at it's antibonding

Answer 7

@abb0t there is indeed a pair of ellectrons in one of the sigma* bond in CN-, what does that implicate? that it will produce a high spin?

Answer 8

This makes the complex, low-spin, meaning splitting energy is large. Also, look at d\(^n\) count. There are quite a bit of things to take into account here when you're looking at this, but yu can always use crystal field theory and MO to explain this. It's a tough concept to explain. I myself do not even know it well. Just from what I was taught in class.

Answer 9

And this was about a year or so ago.

Answer 10

yeah that was what was thought to us to, but the answer sheet provided contradicts.. maybe they just made a mistake then! thank you!(: