## HOOCCH2+, dehydro-acetic acid cation

 O3 / O1 - C2 | / \ H7 C4 - H6 \ H5
The ion charge is 1.

## Atomic Charges and Dipole Moment

O1 charge=-0.274
C2 charge= 0.532
O3 charge=-0.022
C4 charge=-0.298
H5 charge= 0.295
H6 charge= 0.295
H7 charge= 0.472
with a dipole moment of 8.28658 Debye

## Bond Lengths:

between O1 and C2: distance=1.274 ang___ between O1 and O3: distance=2.314 ang___
between O1 and H7: distance=0.991 ang___ between C2 and O3: distance=1.270 ang___
between C2 and C4: distance=1.442 ang___ between O3 and C4: distance=1.631 ang___
between C4 and H5: distance=1.098 ang___ between C4 and H6: distance=1.098 ang___

## Bond Angles:

for O3-C2-O1: angle=130.8 deg___ for C4-C2-O1: angle=155.4 deg___
for H5-C4-C2: angle=119.5 deg___ for H6-C4-C2: angle=119.5 deg___
for H7-O1-C2: angle=114.6 deg___

## Bond Orders (Mulliken):

between O1 and C2: order=1.218___ between O1 and O3: order=-0.117___
between O1 and H7: order=0.769___ between C2 and O3: order=1.488___
between C2 and C4: order=1.193___ between O3 and C4: order=0.620___
between C4 and H5: order=0.899___ between C4 and H6: order=0.899___

## 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 O1-C2 with 1.9978 electrons
__has 64.52% O 1 character in a sp1.97 hybrid
__has 35.48% C 2 character in a sp1.79 hybrid

2. A bonding orbital for O1-H7 with 1.9789 electrons
__has 78.22% O 1 character in a s0.88 p3 hybrid
__has 21.78% H 7 character in a s orbital

3. A bonding orbital for C2-O3 with 1.9869 electrons
__has 34.64% C 2 character in a sp2.53 hybrid
__has 65.36% O 3 character in a sp2.64 hybrid

4. A bonding orbital for C2-O3 with 1.9816 electrons
__has 16.82% C 2 character in a p-pi orbital ( 98.68% p 1.32% d)
__has 83.18% O 3 character in a p-pi orbital ( 99.82% p 0.18% d)

5. A bonding orbital for C2-C4 with 1.9897 electrons
__has 51.84% C 2 character in a sp1.76 hybrid
__has 48.16% C 4 character in a sp2.75 hybrid

6. A bonding orbital for O3-C4 with 1.9305 electrons
__has 72.95% O 3 character in a s0.23 p3 hybrid
__has 27.05% C 4 character in a s0.21 p3 hybrid

7. A bonding orbital for C4-H5 with 1.9855 electrons
__has 63.52% C 4 character in a sp1.98 hybrid
__has 36.48% H 5 character in a s orbital

8. A bonding orbital for C4-H6 with 1.9855 electrons
__has 63.52% C 4 character in a sp1.98 hybrid
__has 36.48% H 6 character in a s orbital

13. A lone pair orbital for O1 with 1.9606 electrons

14. A lone pair orbital for O1 with 1.7668 electrons
__made from a p-pi orbital ( 99.88% p 0.12% d)

15. A lone pair orbital for O3 with 1.9884 electrons

110. A antibonding orbital for C2-O3 with 0.2410 electrons
__has 83.18% C 2 character in a p-pi orbital ( 98.68% p 1.32% d)
__has 16.82% O 3 character in a p-pi orbital ( 99.82% p 0.18% d)

-With core pairs on: O 1 C 2 O 3 C 4 -

#### 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 O1-H7 with the antibonding acceptor orbital, 109, for C2-O3 is 44.2 kJ/mol.

The interaction of bonding donor orbital, 3, for C2-O3 with the antibonding acceptor orbital, 112, for O3-C4 is 24.7 kJ/mol.

The interaction of the second bonding donor orbital, 4, for C2-O3 with the antibonding acceptor orbital, 113, for C4-H5 is 23.0 kJ/mol.

The interaction of the second bonding donor orbital, 4, for C2-O3 with the antibonding acceptor orbital, 114, for C4-H6 is 23.0 kJ/mol.

The interaction of bonding donor orbital, 6, for O3-C4 with the antibonding acceptor orbital, 107, for O1-C2 is 170. kJ/mol.

The interaction of bonding donor orbital, 6, for O3-C4 with the antibonding acceptor orbital, 109, for C2-O3 is 44.3 kJ/mol.

The interaction of lone pair donor orbital, 13, for O1 with the antibonding acceptor orbital, 111, for C2-C4 is 68.1 kJ/mol.

The interaction of the second lone pair donor orbital, 14, for O1 with the second antibonding acceptor orbital, 110, for C2-O3 is 477. 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.

19 ----- -4.485

18 ----- -5.955

17 ----- -8.606

16 ----- -9.287

15 -^-v- -15.49

14 -^-v- -15.68

13 -^-v- -17.36

12 -^-v- -17.70

11 -^-v- -19.06

10 -^-v- -20.07

9 -^-v- -20.60

8 -^-v- -23.89

7 -^-v- -24.95

6 -^-v- -34.85

5 -^-v- -36.33

4 -^-v- -275.7

3 -^-v- -278.2

2 -^-v- -515.8

1 -^-v- -516.1

## 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 = -228.1890019669 Hartrees