Chem 125 Lecture 59/15/06

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Some Resonance Structures for H, C, N, O Isomers

For quantum-calculatedlocal-minimum-energyatomic arrangements

H, C, N, O isomersC in middle

H

C NO :: :

H

C NO:: :

H

C NO::

:

+

_H

C NO :: :

+ _

charge separation charge separation

H

C N O:

:

:

:H C N O:

::

+ _

:H C N O:

: +_

+_ H

C N O::

:

:

+_ H

C N O:

:

:bad charge

sestet

sestet

bad charge

bad charge

H, C, N, O isomersN in middle

H

C NO ::

:: +

_H

C NO

:

::

:

_

+

H

C NO

:

::

:

_

+

H

C NO

:

:

:

:+

_

sestet

sestet

bad charge bad charge

sestet

sestet

H, C, N, O isomersO in middle

HC

N

O

:

:

: H

CN

O: :

+: _

H

CN

O: ::

:sestet

bad charge

H, C, N, O isomerscyclic

H

C

N

O:

:

:

+ _

sestet

H

C

N

O

:

:

:

+

_

:bad charge

Can’t even be calculated(opens up)

HNCOisomers

HC

N

O

:

:

:

H

C NO :: :

H

C NO:: :

H

C N O::

::

H C N O:

::

+ _

H

C NO ::

:

: +_

H

C NO

:

::

:

_

+

H

CN

O: :

+

: _

HNCOisomers

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150

100

50

0

200kc

al/m

ole

H

C N O

H

C NO

H

C NO

H C N O

H

CN

O

H

C NO

H

C NO

HC

N

O

Eca

lc

References:

Most of these structures and energies were calculated at a very high level of theory as reported in Journal of Chemical Physics, 120, 11586-11599 (2004).

The much less stable structures with O in the middle were calculated using the highest level of theory available in the Spartan 04 package of quantum programs. This program could not find an energy minimum for the cyclic structure with H on oxygen.

Levitator by Martin Simon (UCLA)

Eppur sta fermo

J.J. Thomson (1856-1940)

Electron (1897) Plum-Pudding Atom

"[We can] solve the special case where the corpuscles are

confined to a plane."

Thomson's Model of Electron Configuration

"consider the problem as to how 1…2…3…n corpuscles would arrange themselves if placed in a sphere filled with positive electricity of uniform density…"

“distributed in the way most amenable to

mathematical calculation”

in

Vortex Lattice Models (Greg Blonder www.genuineideas.com)

"[We can] solve the special case where the corpuscles are

confined to a plane."

Thomson's Model of Electron Configuration

"consider the problem as to how 1…2…3…n corpuscles would arrange themselves if placed in a sphere filled with positive electricity of uniform density…"

"the equilibrium of eight corpuscles at the corners of a cube is unstable."

in

"I have ever since regarded [the cubic octet]as representing essentially the arrangement

of electrons in the atom"

G. N. Lewis (1923)

Was Lewis ignorant ofEarnshaw's Theorem?

Conclusion of

Valence and the Structure of Atoms and Molecules G. N. Lewis (1923)

"if we use the electron as a test charge to determine the properties of the simplest possible electric field,

namely, the field about a hydrogen nucleus, we appear to find that this field is not a continuum

but is strikingly discontinuous."

The Future of the Quantum TheoryThe Discontinuity of Physico-Chemical Processes

The Electron in Chemistry

J. J. Thomson (1923)

… if [electron-nuclear attraction] were to vary strictly as the inverse square of the distance we know by Earnshaw's theorem than no stable configuration in which the electrons are at rest or oscillating about positions of equilibrium is possible ...

… then a number of electrons can be in equilibrium about a positive charge without necessarily describing orbits around it.

I shall assume that the law of force between a positive charge and an electron is expressed by the equation

F =Eer2 1−

cr

⎛ ⎝

⎞ ⎠

cr

atomic length scaleCouloumb

Quantum Mechanics (1926)

kinetic energy reformulated to explain electron clouds and produce an "inverted"

plum-pudding atom.

Cubic octets and ad hoc force lawssoon disappeared from conventional

Chemistry and Physics

But shared-pairs and lone-pairsremained useful tools for discussing

structure and bonding.

Earnshaw:

No energy minimumfor

point charges

Classical

Despite Earnshaw, might there still be shared-pair bonds

and lone pairs?

How do you know?

By Seeing? Feeling?

Problem:

InconceivablySmall ?

OCCULT CHEMISTRY

A SERIES OF

Clairvoyant Observations on theChemical Elements

BY

ANNIE BESANT, P.T.S.

AND

CHARLES W. LEADBEATER

Reprinted from the Theosophist.

THEOSOPHIST OFFICE, ADYAR, MADRAS, S.

THEOSOPHICAL PUBLISHING SOCIETY, LONDON AND BENARES CITY.

1909 (105 pp.)

1919 (123 pp.)

1951 (400 pp.)

Mrs. AnnieBESANT

P.T.S.(1847-1933)

CuruppumullageJINARAJADASA

P.T.S.(~1877-1953)

"Bishop"Charles WebsterLEADBEATER

(1847 - 1932)

The Occult Chemists (1895-1932)

H O N (1895)18 290 261

Helium72

Lithium127

Iron1008

Neon360

Occult Atoms

4forbital

e-density

Occult Atoms

Bases for Belief:

1) Evidence "cross-examine an assertion"

2) Taste matures with experience

4forbital

e-density

Sodium418

Occult Atoms

Na2CO3(1924)

"note that this trian-gular arrangement of O3 has just been deduced by Bragg from his X-ray analysis of Calcite"

Benzene(1924)

"each of the three valencies of each Carbon are satisfied by Hydrogen, and the fourth valency, which some have postulated as going to the interior of the molecule, does actually do so."

Cf. Wiki: Question 6

“Credit” for use?

Benzene “Resonance”

H

H

H

H

H

H

CC

CC

C

CH

H

H

H

H

H

CC

CC

C

C

H

H

H

H

H

H

CC

CC

C

C

(1889)

1 cm3 of water ≈

1024 molecules

€

10243 =108

molecules / cm

Are Molecules Unobservably Small for

"Vulgar" Eyes?

105

Lecture Room ~10 m

Hair ~100 m

Nucleus ~10 fm

Molecule ~1 nm(small atom ~ 0.1 nm = 1 Å)

101

10-4

105

10-9

105

10-14

105

Query 31

…the Attraction [between glass plates separated by a thin film of Oil of Oranges] may be proportionally greater, and continue to increase until the thickness do not exceed that of a single Particle of the Oil.

3/8 10-6 2.54 cm/inch≈ 10-6 cm = 100 "waters" !

Newton Opticks (1717)

p. 369

flatto

flat

62 mm

convex to

flat

Newton’s Rings

~1 mmgap

at rim

1 mm

p. 175

Newton Opticks (1717)

= cos-1(0.29"/(12"51')) = 89.973°

air gap

0.29"

= (1251)(1-sin ) = 7 10-5 inch = 1.8 m

51'

Simpler Measurementof Smaller Distance

1774

End