4su 2pg 3sg 1pu 2su C 1sg C-C C 4su 2pg 3sg 1pu 2su C 1sg C-C C anti-bonding anti-bonding non-bonding non-bonding Two “lone pairs” but not equivalent! bonding Two “O-H bonds” bonding Mainly B 2p lcao’s Note p bonds! Mainly B 2s-F 2p lcao’s Mainly F 2s lcao’s.

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Transcript 4su 2pg 3sg 1pu 2su C 1sg C-C C 4su 2pg 3sg 1pu 2su C 1sg C-C C anti-bonding anti-bonding non-bonding non-bonding Two “lone pairs” but not equivalent! bonding Two “O-H bonds” bonding Mainly B 2p lcao’s Note p bonds! Mainly B 2s-F 2p lcao’s Mainly F 2s lcao’s.

4su
2pg
3sg
1pu
2su
C
1sg
C-C
C
4su
2pg
3sg
1pu
2su
C
1sg
C-C
C
anti-bonding
anti-bonding
non-bonding
non-bonding
Two
“lone pairs”
but not equivalent!
bonding
Two
“O-H bonds”
bonding
Mainly
B 2p lcao’s
Note p bonds!
Mainly
B 2s-F 2p
lcao’s
Mainly
F 2s lcao’s
L a.o.’s
M a.o.’s
ML4 - D4h
L a.o.’s
M a.o.’s
ML4 - D4h
a1
z
F
g
t1u
eg
3d t2g
S
F
F
eg
t2g
x
F
3p t1u
3s a1g
eg
t1u
a1g
eg
.F
Oh
S valence orbitals (9)
y
F
F
t1u
F donor (sp) orbitals (6)
a1g
SF6
Instead of;
. F
2p
Because harder to draw
a1
g
t1u
3d
eg
eg
t2g
t2g
3p t1u
3s a1
g
eg
t1u
a1
eg
g
Bonding MO’s
8 e- gives 4 bonds!
Oh
t1u
a1
g
SF6
. F
a1
F
g
F
F
t1u
S
F
F
F
Two views:
A) 4 bonds distributed over
six S-F pairs
B) 4 bonds (covalent ) +
2 “bonds” ionic (S6+-F-)
3p t1u
3s a1
g
eg
t1u
a1
eg
g
t1u
a1
g
SF6
3s
Na
I
Br (-12.5 eV)
Cl (-13.7 eV)
F-
F (-18.6 eV)
4p t1u
4s a1
g
eg
3d
t2g
eg
t1u
a1
3rd row M,
Valence
Atomic
orbitals
g
Oh
ML6
:L
6s-donors
s ONLY,
Like H or NH3
Symmetry Adapted Group Orbitals for 6 s-donors
t1u
a1
g
eg
4p t1u
4s a1
g
eg
3d
t2g
t2g
eg
t1u
a1
3rd row M,
Valence
Atomic
orbitals
g
eg
Oh
t1u
a1
g
ML6
:L
6s-donors
s ONLY,
Like H or NH3
t1u
a1
M-L s anti-bonding MO’s
g
eg
4p t1u
4s a1
g
eg
3d
t2g
3rd row M,
Valence
Atomic
orbitals
M-L s bonding MO’s
t2g
eg
t1u
a1
eg
g
Oh
t1u
a1
g
ML6
:L
6s-donors
s ONLY,
Like H or NH3
t1u
a1
M-L s anti-bonding MO’s
g
eg
4p t1u
What is Do?
4s a1
g
eg
3d
t2g
3rd row M,
Valence
Atomic
orbitals
M-L s bonding MO’s
t2g
eg
t1u
a1
eg
g
Oh
t1u
a1
g
ML6
:L
6s-donors
s ONLY,
Like H or NH3
Symmetry Adapted Group Orbitals for 6 p-donors
t1u
a1
M-L s anti-bonding MO’s
g
eg
4p t1u
4s a1
g
eg
3d
t2g
3rd row M,
Valence
Atomic
orbitals
M-L s bonding MO’s
t2g
eg
t1u
a1
g
t2g
t2u
t1g
t1u
12 L
p orbitals
eg
t1u
a1
g
Oh
:L
6s
p-donors
Like Cl-
..
L
t1u
a1
M-L s anti-bonding MO’s
g
eg
4p t1u
4s a1
Effect on Do?
t2g
g
eg
3d
t2g
3rd row M,
Valence
Atomic
orbitals
M-L s bonding MO’s
t2g
eg
t1u
a1
g
t2g
t2u
t1g
t1u
12 L
p orbitals
eg
t1u
a1
g
Oh
:L
6s
p-donors
Like Cl-
t1u
a1
M-L s anti-bonding MO’s
g
eg
4p t1u
CO
t2g
4s a1
t2g
t2u
t1g
t1u
12 L
p orbitals
g
eg
3d
t2g
t2g
3rd row M,
Valence
Atomic
orbitals
M-L s bonding MO’s
t2g
t2u
t1g
t1u
12 L
p orbitals
eg
t1u
a1
eg
g
Oh
t1u
:L
6s
p-acceptors
Like CO, CN-
a1
g
ML6
eg
eg
eg
t2g
Do
Do
t2g
t2g
eg
eg
t2g
t2g
3d
eg
t2g
t2g
3d
t2g
t2g
Case 1.
L is p innocent
(sigma donor only)
Do
Case 2.
L is p base
(sigma donor and
p donor)
3d
t2g
12 L
p
orbitals
Case 3.
L is p acid
(sigma donor and
p acceptor)
12 L
p
orbitals