## C2H3O+ cation*

 H6 O3 \ / | H5 - C1 - C2 \ H4
The ion charge is 1.

## Atomic Charges and Dipole Moment

C1 charge=-0.235
C2 charge= 0.384
O3 charge= 0.014
H4 charge= 0.236
H5 charge= 0.299
H6 charge= 0.299
with a dipole moment of 4.02451 Debye

## Bond Lengths:

between C1 and C2: distance=1.439 ang___ between C1 and O3: distance=1.647 ang___
between C1 and H5: distance=1.099 ang___ between C1 and H6: distance=1.099 ang___
between C2 and O3: distance=1.253 ang___ between C2 and H4: distance=1.103 ang___

## Bond Angles:

for O3-C2-C1: angle=75.06 deg___ for H4-C2-O3: angle=131.7 deg___
for H5-C1-O3: angle=111.1 deg___ for H6-C1-H5: angle=121.0 deg___

## Bond Orders (Mulliken):

between C1 and C2: order=1.196___ between C1 and O3: order=0.556___
between C1 and H5: order=0.888___ between C1 and H6: order=0.888___
between C2 and O3: order=1.551___ between C2 and H4: order=0.868___

## 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.

### Hybridization in the Best Lewis Structure

1. A bonding orbital for C1-C2 with 1.9882 electrons
__has 49.21% C 1 character in a sp2.57 hybrid
__has 50.79% C 2 character in a sp2.02 hybrid

2. A bonding orbital for C1-O3 with 1.9513 electrons
__has 24.33% C 1 character in a s0.16 p3 hybrid
__has 75.67% O 3 character in a s0.22 p3 hybrid

3. A bonding orbital for C1-H5 with 1.9869 electrons
__has 63.54% C 1 character in a sp1.99 hybrid
__has 36.46% H 5 character in a s orbital

4. A bonding orbital for C1-H6 with 1.9869 electrons
__has 63.54% C 1 character in a sp1.99 hybrid
__has 36.46% H 6 character in a s orbital

5. A bonding orbital for C2-O3 with 1.9897 electrons
__has 33.43% C 2 character in a sp2.75 hybrid
__has 66.57% O 3 character in a sp2.38 hybrid

6. A bonding orbital for C2-O3 with 1.9817 electrons
__has 21.35% C 2 character in a p-pi orbital ( 98.79% p 1.21% d)
__has 78.65% O 3 character in a p-pi orbital ( 99.80% p 0.20% d)

7. A bonding orbital for C2-H4 with 1.9949 electrons
__has 64.49% C 2 character in a sp1.47 hybrid
__has 35.51% H 4 character in a s orbital

11. A lone pair orbital for O3 with 1.9908 electrons

-With core pairs on: C 1 C 2 O 3 -

#### 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 bonding donor orbital, 2, for C1-O3 with the antibonding acceptor orbital, 88, for C2-O3 is 54.3 kJ/mol.

The interaction of bonding donor orbital, 2, for C1-O3 with the antibonding acceptor orbital, 90, for C2-H4 is 97.0 kJ/mol.

The interaction of bonding donor orbital, 5, for C2-O3 with the antibonding acceptor orbital, 85, for C1-O3 is 25.2 kJ/mol.

The interaction of the second bonding donor orbital, 6, for C2-O3 with the antibonding acceptor orbital, 86, for C1-H5 is 24.6 kJ/mol.

The interaction of the second bonding donor orbital, 6, for C2-O3 with the antibonding acceptor orbital, 87, for C1-H6 is 24.5 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.

15 ----- -4.320

14 ----- -5.300

13 ----- -9.254

12 ----- -11.12

11 -^-v- -16.21

10 -^-v- -16.72

9 -^-v- -18.76

8 -^-v- -20.17

7 -^-v- -20.53

6 -^-v- -23.03

5 -^-v- -25.34

4 -^-v- -36.67

3 -^-v- -276.1

2 -^-v- -277.8

1 -^-v- -516.9

## 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 = -152.8925414948 Hartrees

* This ion can result from the rearrangment of +CH2CH=O from a corresponding aldehyde radical cation:
R-CH2-CH2-CH=O+• -> R-CH2• + +CH2CH=O
or from hydride abstraction from acetaldehyde, CH3CH=O, or from hydride abstraction from ethylene oxide: H2C/O\CH2.