## CH3CH2O-, ethoxide anion

 H3 H8 O7 \ | / H5 - C1 - C2 / | H4 H6
The ion charge is -1.

## Atomic Charges and Dipole Moment

C1 charge=-0.220
C2 charge= 0.712
H3 charge= 0.001
H4 charge= 0.002
H5 charge=-0.060
H6 charge=-0.214
O7 charge=-1.007
H8 charge=-0.213
with a dipole moment of 3.58488 Debye

## Bond Lengths:

between C1 and C2: distance=1.582 ang___ between C1 and H3: distance=1.108 ang___
between C1 and H4: distance=1.108 ang___ between C1 and H5: distance=1.116 ang___
between C1 and H6: distance=2.173 ang___ between C1 and O7: distance=2.460 ang___
between C1 and H8: distance=2.171 ang___ between C2 and H6: distance=1.152 ang___
between C2 and O7: distance=1.349 ang___ between C2 and H8: distance=1.152 ang___

## Bond Angles:

for H3-C1-C2: angle=109.0 deg___ for H4-C1-C2: angle=109.0 deg___
for H5-C1-C2: angle=113.0 deg___ for H6-C2-C1: angle=104.1 deg___
for O7-C2-C1: angle=113.9 deg___ for H8-C2-C1: angle=104.0 deg___

## Bond Orders (Mulliken):

between C1 and C2: order=0.746___ between C1 and H3: order=0.990___
between C1 and H4: order=0.990___ between C1 and H5: order=0.977___
between C1 and H6: order=-0.053___ between C1 and O7: order=-0.136___
between C1 and H8: order=-0.053___ between C2 and H6: order=1.011___
between C2 and O7: order=1.210___ between C2 and H8: order=1.011___

## Best Lewis Structure

The Lewis structure that is closest to your structure is determined. The hybridization of the atoms in this idealized Lewis structure is given in the table below. Please note that your structure can't be well described by a single Lewis structure, because of extensive delocalization.

### Hybridization in the Best Lewis Structure

1. A bonding orbital for C1-C2 with 1.9946 electrons
__has 54.54% C 1 character in a sp2.33 hybrid
__has 45.46% C 2 character in a sp2.75 hybrid

2. A bonding orbital for C1-H3 with 1.9934 electrons
__has 57.91% C 1 character in a s0.92 p3 hybrid
__has 42.09% H 3 character in a s orbital

3. A bonding orbital for C1-H4 with 1.9934 electrons
__has 57.92% C 1 character in a s0.92 p3 hybrid
__has 42.08% H 4 character in a s orbital

4. A bonding orbital for C1-H5 with 1.9947 electrons
__has 56.44% C 1 character in a s0.90 p3 hybrid
__has 43.56% H 5 character in a s orbital

5. A bonding orbital for C2-H6 with 1.9848 electrons
__has 52.72% C 2 character in a s0.80 p3 hybrid
__has 47.28% H 6 character in a s orbital

6. A bonding orbital for C2-O7 with 1.9971 electrons
__has 39.10% C 2 character in a sp2.14 hybrid
__has 60.90% O 7 character in a sp2.21 hybrid

7. A bonding orbital for C2-H8 with 1.9847 electrons
__has 52.71% C 2 character in a s0.80 p3 hybrid
__has 47.29% H 8 character in a s orbital

11. A lone pair orbital for O7 with 1.9852 electrons

12. A lone pair orbital for O7 with 1.9009 electrons
__made from a p-pi orbital ( 99.96% p)

13. A lone pair orbital for O7 with 1.9000 electrons

-With core pairs on: C 1 C 2 O 7 -

#### Donor Acceptor Interactions in the Best Lewis Structure

The localized orbitals in your best Lewis structure can interact strongly. A filled bonding or lone pair orbital can act as a donor and an empty or filled bonding, antibonding, or lone pair orbital can act as an acceptor. These interactions can strengthen and weaken bonds. For example, a lone pair donor->antibonding acceptor orbital interaction will weaken the bond associated with the antibonding orbital. Conversly, an interaction with a bonding pair as the acceptor will strengthen the bond. Strong electron delocalization in your best Lewis structure will also show up as donor-acceptor interactions.
Interactions greater than 20 kJ/mol for bonding and lone pair orbitals are listed below.

The interaction of the second lone pair donor orbital, 12, for O7 with the antibonding acceptor orbital, 100, for C2-H6 is 98.7 kJ/mol.

The interaction of the second lone pair donor orbital, 12, for O7 with the antibonding acceptor orbital, 102, for C2-H8 is 82.8 kJ/mol.

The interaction of the third lone pair donor orbital, 13, for O7 with the antibonding acceptor orbital, 96, for C1-C2 is 97.9 kJ/mol.

The interaction of the third lone pair donor orbital, 13, for O7 with the antibonding acceptor orbital, 100, for C2-H6 is 24.9 kJ/mol.

The interaction of the third lone pair donor orbital, 13, for O7 with the antibonding acceptor orbital, 102, for C2-H8 is 41.2 kJ/mol.

## Molecular Orbital Energies

The orbital energies are given in eV, where 1 eV=96.49 kJ/mol. Orbitals with very low energy are core 1s orbitals. More antibonding orbitals than you might expect are sometimes listed, because d orbitals are always included for heavy atoms and p orbitals are included for H atoms. Up spins are shown with a ^ and down spins are shown as v.

17 ----- 8.484
16 ----- 8.117

15 ----- 6.896
14 ----- 6.377

13 -^-v- 2.161
12 -^-v- 2.041

11 -^-v- -1.888

10 -^-v- -2.686

9 -^-v- -3.183

8 -^-v- -4.634

7 -^-v- -5.040

6 -^-v- -8.033

5 -^-v- -11.84

4 -^-v- -16.09

3 -^-v- -260.6

2 -^-v- -261.1

1 -^-v- -497.1

## Total Electronic Energy

The total electronic energy is a very large number, so by convention the units are given in atomic units, that is Hartrees (H). One Hartree is 2625.5 kJ/mol. The energy reference is for totally dissociated atoms. In other words, the reference state is a gas consisting of nuclei and electrons all at infinite distance from each other. The electronic energy includes all electric interactions and the kinetic energy of the electrons. This energy does not include translation, rotation, or vibration of the the molecule.

Total electronic energy = -154.4793056652 Hartrees