Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s...

41
Welcome to 3.091 Lecture 10 September 30, 2009 Hybridized & Molecular Orbitals; Paramagnetism

Transcript of Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s...

Page 1: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Welcome to 3.091Lecture 10

September 30, 2009

Hybridized & Molecular Orbitals; Paramagnetism

Page 2: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

3.091 Test #1 Wednesday, October 7, 2009

Room Assignments

A – Ha: 10-250

He - Sm: 26-100

So - ∞: 4-270

Page 3: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Increasing

Electronegativity, χ

Incr

easi

ng

s Block p Block d Block f Block

Image by MIT OpenCourseWare.

Page 4: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Image by MIT OpenCourseWare.

Page 5: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Group Classifications6

Atomic Number2

Oxidation States3

Symbol4

Electronic5

Configuration

Name4

bold indicatesmost stable state

Black = solid, red = gas,blue = liquid,outline = syntheticallyprepared

25

7VIIAVIIB

Mn

Atomic Weight1

Melting Point7, OC

Boiling Point7, OC

Density8, g/cm3

Electronegativity9

First lonizationPotential10, eV

(gases: g/L at 0OC, 1atm)

( ) Indicates most stableor best known isotope

54.93805

Manganese

124620617.471.55

7.435[Ar]3d54s2

2, 3, 4, 6, 7

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Page 6: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

huh?

100

75

50

25

00.5 1.0 1.5 2.0 2.5 3.0 3.5

KF

CsF

LiFNaClKClCsCl

LiClCsIKBr

KI

LiI

HF

IFHCl

HBrIClHIIBr

LiBr

Perc

ent i

onic

cha

ract

er

Electronegativity difference

Huh?

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Page 7: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

H 1s H 1s

H2

Electron-Pair Bond

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Page 8: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Ha

Hb

1sa

1sb

1sa

1sb

+ = MO I

Molecular Orbital _______ Bonding

Image by MIT OpenCourseWare.

Page 9: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Image by MIT OpenCourseWare.

Page 10: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Copyright © 2003 John Wiley & Sons, Inc. Reprinted with permission of John Wiley & Sons., Inc. Source: Spencer, J. N., G. M. Bodner, and L. H. Rickard. Chemistry: Structure and Dynamics. 2nd edition. New York, NY: John Wiley & Sons, 2003.

Page 11: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

E1s 1s

H (AO) H (AO)H2 (MOs)

σ1s

σ1s∗

+

+ -

Image by MIT OpenCourseWare.

Page 12: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

E1s 1s

He (AO) He (AO)He2 (MOs)

(c)

σ1s

σ1s∗

Image by MIT OpenCourseWare.

Page 13: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

E1s 1s

He (AO) He+ (AO)He2+ (MOs)

(b)

σ1s

σ1s∗

Image by MIT OpenCourseWare.

Page 14: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Image by MIT OpenCourseWare.

Page 15: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Copyright © 2003 John Wiley & Sons, Inc. Reprinted with permission of John Wiley & Sons., Inc. Source: Spencer, J. N., G. M. Bodner, and L. H. Rickard. Chemistry: Structure and Dynamics. 2nd edition. New York, NY: John Wiley & Sons, 2003.

Page 16: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Bonding

Atomic orbitals Molecular orbital

_

X

Z

σnpz

Z

X

npz

Z

X

npz

Image by MIT OpenCourseWare.

Page 17: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Copyright © 2003 John Wiley & Sons, Inc. Reprinted with permission of John Wiley & Sons., Inc. Source: Spencer, J. N., G. M. Bodner, and L. H. Rickard. Chemistry: Structure and Dynamics. 2nd edition. New York, NY: John Wiley & Sons, 2003.

Page 18: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

2pxa2pxb

π2px

π2px* Antibonding

BondingLobes

Lobes

Nodal Plane

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Page 19: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

X

Z +

npx

X

Z

npx

X

Z

πnpx

X

Z +

npy

X

Z

npy

X

Z

πnpy

Bonding

Atomic orbitals Molecular orbitals

Image by MIT OpenCourseWare.

Page 20: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

2p 2p

σ2p*

σ2p

σ2s*

σ2s

πx*

πx

πy*

πy

2s 2s

e.g. N2, B2, C2

Image by MIT OpenCourseWare.

Page 21: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

2p 2p

σ2p*

σ2s*

σ2s

σ2p

πx* πy*

2s 2s

6 bonding electrons

=> triple bond

N N946 kJ/mol

N2

Image by MIT OpenCourseWare.

Page 22: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

2p 2p

σ2p*

σ2s*

σ2s

σ2p

πx*

πx

πy*

πy

2s 2s

e.g. O2 & F2

Image by MIT OpenCourseWare.

Page 23: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

σ2p*

σ2p

πx*

πx

πy*

πy

σ2p*

σ2p

πx*

πx

πy*

πy

Image by MIT OpenCourseWare.

Page 24: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

2s-2pz interaction

Li2 Be2 B2 C2 N2 O2 F2

E

σ2pz∗

σ2s∗

σ2s

σ2pz

π2px,y∗

π2px,y

Image by MIT OpenCourseWare.

Page 25: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

2p 2p

σ2p*

σ2s*

σ2s

σ2p

πx* πy*

πx πy

2s 2s

6 bonding electrons2 anti bonding electrons

=> double bond

498 kJ/mol

O2

0 = 0

Image by MIT OpenCourseWare.

Page 26: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

2p 2p

σ2p*

σ2s*

σ2s

σ2p

πx* πy*

πx πy

2s 2s

6 bonding electrons4 anti bonding electrons

=> single bond

160 kJ/mol

F2

F-F

Image by MIT OpenCourseWare.

Page 27: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Image by MIT OpenCourseWare.

Page 28: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

paramagnetism in liquid oxygen

2p 2p

σ2p*

σ2s*

σ2s

σ2p

πx* πy*

πx πy

2s 2s

6 bonding electrons2 anti bonding electrons

=> double bond

498 kJ/mol

O2

0 = 0

Image by MIT OpenCourseWare.

Averill, B., and P. Eldredge. Chemistry: Principles, Patterns, andApplications. Flat WorldKnowledge, 2011. ISBN: 9781453331224.

Page 29: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

An sp2 Hybrid Orbital

Three sp2

Hybrid OrbitalsHybridization

2py

2px

2s

sp2

sp2

sp2 An sp2-Hybridized Atom

Side View

90o

p

Image by MIT OpenCourseWare.

Page 30: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Sp2

Sp2Sp2 Z

P

Top View

C120o

120o

120o

Image by MIT OpenCourseWare.

Page 31: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Sp2

Sp2 Sp2Sp2 Sp2

Sp2

Sp2

Image by MIT OpenCourseWare.

Page 32: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Sp2

Sp2 Sp2

Sp2

Sp2

Image by MIT OpenCourseWare.

Page 33: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Sp2

Sp2

Sp2

Sp2Sp2

Image by MIT OpenCourseWare.

Page 34: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Image by MIT OpenCourseWare.

Page 35: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Figure 9.29

CCC CH

H

H

H

2pz 2pzH 1s

H 1s

H 1s

H 1s

sp2 sp2

z

(b) C2H4 pi bonding(a) C2H4 sigma-bonded framework

Image by MIT OpenCourseWare.

Page 36: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

metallic melt turns into molten salt!! clear, colorless liquid big drop in electrical conductivity shift from electronic to ionic conduction cesium auride

Extremes in electronegativity NaI: Δχ = 1.73

CsAu: Δχ = 1.75

Cs and Au, both metals, melt to form metallic liquids, but…when the concentration nears 50%

(equal numbers of donors & acceptors) electron transfer occurs !

Page 37: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Extremes in electronegativity NaI: Δχ = 1.73

CsAu: Δχ = 1.75

Cs and Au, both metals, melt to form metallic liquids, but…when the concentration nears 50%

(equal numbers of donors & acceptors) electron transfer occurs !

metallic melt turns into molten salt!! clear, colorless liquid big drop in electrical conductivity shift from electronic to ionic conduction cesium auride

Page 38: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Specific electrical conductivity of liquid Cs _ Au alloys as a function of concentration

105

104

103

102

10

105

104

103

102

10

1110 30 50 70 90

10 30 50 70 90

Cs Au

( Hoshino et al. 1975)

600oC

At % Au

σ o

hm-1

cm-1

Electronic conductivity

Ionic conductivityMolten salt

Liquid metal

Image by MIT OpenCourseWare.

Page 39: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Extremes in electronegativity NaI: Δχ = 1.73

CsAu: Δχ = 1.75

Cs and Au, both metals, melt to form metallic liquids, but…when the concentration nears 50%

(equal numbers of donors & acceptors) electron transfer occurs !

metallic melt turns into molten salt!! clear, colorless liquid big drop in electrical conductivity shift from electronic to ionic conduction cesium auride

Page 40: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

Extremes in electronegativity NaI: Δχ = 1.73

CsAu: Δχ = 1.75

Cs and Au, both metals, melt to form metallic liquids, but…when the concentration nears 50%

(equal numbers of donors & acceptors) electron transfer occurs !

metallic melt turns into molten salt!! clear, colorless liquid big drop in electrical conductivity shift from electronic to ionic conduction cesium auride

Page 41: Welcome to 3 · Atomic orbitals Molecular orbitals Image by MIT OpenCourseWare. 2p 2p s 2p* s 2p s 2s* s 2s px* px py* py 2s 2s e.g. N 2, B 2, C 2 ... Hybrid Orbital Three sp2 Hybrid

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