TRANSITION METALS Explaining colour Using the key words: Absorbed, transmitted and reflected explain the colours in each of the following:
TRANSITION METALS E x p l a i n i n g c o l o u r
Feb 22, 2016
TRANSITION METALS E x p l a i n i n g c o l o u r. Using the key words: Absorbed , transmitted and reflected explain the colours in each of the following:. Use these 6 pictures to work out the three factors that affect the colour of a transition metal compound…. FeCl 2. MnCl 2. FeCl 2. - PowerPoint PPT Presentation
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TRANSITION METALSExplaining colour
Using the key words: Absorbed, transmitted and reflected explain the colours in each of the following:
MnCl2 FeCl2
FeCl2 FeCl3
FeCl3 Fe(NO3)3
Use these 6 pictures to work out the three factors that affect the colour of a transition metal compound…
MnCl2 FeCl2
FeCl2 FeCl3
FeCl3 Fe(NO3)3
Use these 6 pictures to work out the three factors that affect the colour of a transition metal compound…
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
2NH3 4NH3
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG BG
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG
RBG BG
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG
RBG BG B
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG
RBG BG B
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG
RBG BG B
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG
RBG BG B
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG
RBG BG B
Describe what happens to the average frequency of visible light absorbed as you increase the number of NH3 ligands…
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG
RBG BG B
Describe what happens to the average frequency of visible light absorbed as you increase the number of NH3 ligands…
[Cu(H2O)6]2+(aq) [Cu(OH)2(H2O)4](s) [Cu(NH3)4(H2O)2]2+(aq)
Explaining the colour-ligand relationship
RBG
RBG BG B
Describe what happens to the average frequency of visible light absorbed as you increase the number of NH3 ligands…
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
Ligand field theory
Ligand field theory
The negative charge due to the lone pair affects the orbitals energy differently
Ligand field theory
The negative charge due to the lone pair affects the orbitals energy differentlyWhen ligands approach orbitals that have lobes along the axes the energy is raised
Ligand field theory
The negative charge due to the lone pair affects the orbitals energy differentlyWhen ligands approach orbitals that have lobes along the axes the energy is raised
Ligand field theory
The negative charge due to the lone pair affects the orbitals energy differentlyWhen ligands approach orbitals that have lobes along the axes the energy is raised When ligands approach orbitals that have lobes between the axes the energy is lowered
Ligand field theory
The negative charge due to the lone pair affects the orbitals energy differentlyWhen ligands approach orbitals that have lobes along the axes the energy is raised When ligands approach orbitals that have lobes between the axes the energy is lowered
SUMMARY• When the 5 d-orbitals are free of ligands they are of equal energy
(degenerate)• When the d-orbitals are surrounded by ligands the energy is split.• Two orbitals are higher in energy and three orbitals are lower.
Ligand field theory
The negative charge due to the lone pair affects the orbitals energy differentlyWhen ligands approach orbitals that have lobes along the axes the energy is raised When ligands approach orbitals that have lobes between the axes the energy is lowered
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
What is the electron configuration of a Cu2+
ion? (spdf notation)
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
Ammonia is a stronger base that water. Predict the effect that this will have on the energy difference between the spit orbitals…
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
What happens next? Many sources explain that the electron de-excites and re-emits light. The problem with this is that the same frequency of light would be emitted as was absorbed in the first place and no net absorption would take place so the compound would be colourless. Other mechanisms of de-excitation are being investigated such as collisional de excitation
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
Ener
gy
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
Ener
gy
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
Absorbed low frequency Absorbed high frequency
The average frequency of visible light absorbed INCREASES when you substitute H2O ligands with NH3 ligands.
Absorbed low frequency Absorbed high frequency
General rule of colour of aqueous octahedral complexes
The more ligand molecules that are stronger lewis basesThe colour shifts towards the high frequency / high energy end of the spectrum
Example question
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