The spectrochemical series for ligands and metals

Question 1

What impact does the ligand have on CS

Answer 1

1. CFT treats all ligands as being identical point charges
2. But ligand has impact on the size of CFS
3. The energy of the lowest-energy electronic transition (Do) increases as the ligand series varies

Question 2

How does the variation change with different metal ions

Answer 2

1. The variation is general for the same order of ligands regardless of the metal ion

Question 3

How can ligands be arranged

Answer 3

1. In order of increasing transition energy (Do, Dt etc) when they are present in a complex
2. The spectrochemical series for ligands

Question 4

Which ligand has the smallest Do

Answer 4

1. I-

Question 5

Which ligand has the largest Do

Answer 5

1. CO

2. Has a much greater effect on CS

Question 6

What does the colour of solution of complex correspond to

Answer 6

1. opposite to colour that is absorbed by complex
2. Linked to E=HV
3. v=C/lambda

Question 7

What else impacts the size of the crystal field splitting

Answer 7

1. The values of Do or Dt depend in a systematic way on the metal ion
2. Do and Dt increase with increasing oxidation state of the metal
3. Do and Dt also increase as you go down a group

Question 8

Why do Do and Dt increase with increasing oxidation state

Answer 8

1. Higher charged cations have smaller radii and hence shorter M-L distances

Question 9

Why do Do and Dt increase as you go down the group

Answer 9

1. M-L bonding improves due to more expanded 4d and 5d orbitals

Question 10

Which ions have the smallest Do

Answer 10

1. Ions with +2 charge and 3d orbitals

Question 11

Which group of ions have the next smallest Do

Answer 11

1. ions with +3 charge and 3d orbitals

Question 12

Which group of ions have the second largest Do

Answer 12

1. ions with +4 charge and 4d orbitals

Question 13

Which group of ions have the largest Do

Answer 13

1. ions with +3/4 charge and 5d orbitals