1
A students work (without solutions manual) 10
problems/night.
Dr. Alanah Fitch Flanner Hall 402 508-3119 afitch_at_
luc.edu Office Hours ThF 2-330 pm
Module 18B Color
2
Biological Nutrients
Zn 138
Cu 128
Fe 126
Ni 124
Ti
V
Cr 130
Mn 135
Co 125
Sc
Nearly All involved in color
Industrially Important
3
Two competing Trends
Why do electrons get pulled in?
More Nuclear Charge holding electrons in closer
More Electrons
Pattern for number of oxidation states
Related to shape of orbitals! Inability to
shield added positive charge in the nucleus
4
Transition Metals 5 orbitals (10 electrons)
1. d block guys (and gals) 2. d orbitals are
clover leaf in shape 3. How well does the orbital
shield or cover the positive charge of the
nucleus?
z
z
x2-y2
xy
x
x
y
y
z
z
yz
x
y
xz
5
z
xy
x
Enter on x,y,z axis
y
Cl begins Approach to minimize charge repulsion
How will the incoming Cl- interact individually
with the 5 d orbitals?
6
Incoming Cl- see little e
Incoming Cl- bumps into d orbital e
7

1. Initially all orbitals same energy
2. Incoming anion interacts with d orbitals
3. Energy levels change due to the interaction
4. 3 orbitals move down in energy
5. 2 move up

8
Suppose it is NH3 instead of Cl- What do you
think will happen?
z2
Greater Orbital Splitting with Nitrogen charge
dense lone pair (localized)
D orbital energy in absence of ligands
CN-gtNO2-gtengtNH3gtNCS-gtH2OgtF-gtOH-gtCl-gtSCN-gtS2-gtBr-gtI
-
Strong field
Weak field
Explain what you observe for F,Cl, Br,I
9
Crazy Painters
Bernardino Ramazzini 1633-1714 De Morbis
artificum diatriba Vernatti Report to Royal
Society White lead manufacture illnesses 1678
Goyas Saturn
10
The Artists Palette (lt1850)
5 Primary colors blue various copper
coordination complex
11
Copper Coordination Complexes Blue
Cu2 s0d9
?
D orbitals with no ligands near by
decreasing Electron energy (stable orbitals)
12
How our eyes sense light 1.Pure pink light is
emitted between 400-430 2.Eyes will see this as
pink 3.The brain also perceives pink when the
eyes see light in which the wavelengths at 500
and above 650 are removed. 4. The brain is
adding up total voltage signals from three
different receptors (blue, green, and red) 5.
Total voltage is similar to that for pure pink
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The Artists Palette (lt1850)
5 Primary colors blue various copper
coordination complexes red Minium Pb22P
b4O3
15
2e
16
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The Artists Palette (lt1850)
5 Primary colors blue various copper
coordination complexes red Minium Pb22P
b4O3 yellow Litharge PbO Yellow
Chrome PbCrO4 Lead Antimonate, Lead Tin I,
Lead Tin II
18
Charge Transfer Based Colors
Metal to Ligand Charge Transfer
Intervalence Charge Transfer
Each one of these has an oxidation/reduction Energ
y low enough to be excited by visible radiation
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Electron transfer drives color
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Chromium
1. Identified when found as the mineral crocoite
in late 1700s (PbCrO4) 2. Main oxidation
states s2d4 0 s0d0 6 s2d1 3
Cr6O42-
Note electrons on Oxygen pointing in
toward cationic Cr6
22
1. Can Oxygen anion give electrons to
chromium?, 2. What would be the
energy/electron? 3. What wavelength would that
translate to?
23
F9.6485x104
24
why does a fire look red-hot? Wavelength
Absorbed Observed Color Violet 400- 460
nm greenish-yellow Indigo Blue 450-490 red Gre
en 490-570 violet Yellow 570-590 dark
blue Orange 590-610 blue Red 610-700 green
absorb high energy, short wavelength (lt400
nm) observe red
What color does CrO42- give us?
25
Mix for orange
Mix for green
The Artists Palette (lt1850)
5 Primary colors blue various copper
coordination complexes red Minium Pb22P
b4O3 yellow Litharge PbO Yellow
Chrome PbCrO4 Lead Antimonate, Lead Tin I,
Lead Tin II Black Kohl, PbS
26
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Mix for orange
Mix for green
The Artists Palette (lt1850)
5 Primary colors blue various copper
coordination complexes red Minium Pb22P
b4O3 yellow Litharge PbO Yellow
Chrome PbCrO4 Lead Antimonate, Lead Tin I,
Lead Tin II Black Kohl, PbS White cerruse
PbCO3
28
Cu2 s0d9
Pb2 s2d10p0
?
Which one has electrons that can be promoted and
has space in the higher orbital to accept an
electron?
29
Lead crocoite
Lead wulfenite
Lead carbonate
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Where did all the lead go?
Decade Estimate lbs white
lead/housing unit 1914-23
110 1920-29 87 1930-39
42 1940-49
22 1950-59 7 1960-69
3 1970-1979
1
TiO2 makes inroads particularly in Europe
White lead restricted
Chicago Soils
33
Replacement pigment TiO2
Ti2 s2d0
Cu2 s0d9
Pb2 s2d10p0
?
Which one has electrons that can be promoted and
has space in the higher orbital to accept an
electron?
34
A students work (without solutions manual) 10
problems/night.
Dr. Alanah Fitch Flanner Hall 402 508-3119 afitch_at_
luc.edu Office Hours ThF 2-330 pm
Module 18 Color chemistry