## HOCO-

 H3 O4 | // O1 - C2
The ion charge is -1.

## Atomic Charges and Dipole Moment

O1 charge=-0.567
C2 charge=-0.392
H3 charge= 0.339
O4 charge=-0.378
with a dipole moment of 2.35792 Debye

## Bond Lengths:

between O1 and C2: distance=1.508 ang___ between O1 and H3: distance=0.996 ang___
between C2 and H3: distance=1.974 ang___ between C2 and O4: distance=1.250 ang___

## Bond Angles:

for H3-O1-C2: angle=102.1 deg___ for O4-C2-O1: angle=109.5 deg___

## Bond Orders (Mulliken):

between O1 and C2: order=0.311___ between O1 and H3: order=0.862___
between C2 and H3: order=0.090___ between C2 and O4: order=1.438___

## 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 1.9941 electrons
__has 75.59% O 1 character in a sp2.49 hybrid
__has 24.41% C 2 character in a s0.55 p3 hybrid

2. A bonding orbital for O1-H3 with 1.9950 electrons
__has 72.20% O 1 character in a s0.80 p3 hybrid
__has 27.80% H 3 character in a s orbital

3. A bonding orbital for C2-O4 with 1.9993 electrons
__has 19.28% C 2 character in a p-pi orbital ( 99.05% p 0.95% d)
__has 80.72% O 4 character in a p-pi orbital ( 99.86% p 0.14% d)

4. A bonding orbital for C2-O4 with 1.9954 electrons
__has 30.97% C 2 character in a sp2.45 hybrid
__has 69.03% O 4 character in a sp1.50 hybrid

8. A lone pair orbital for O1 with 1.9930 electrons

9. A lone pair orbital for O1 with 1.9344 electrons
__made from a p-pi orbital ( 99.96% p)

10. A lone pair orbital for C2 with 1.9754 electrons

11. A lone pair orbital for O4 with 1.9838 electrons

12. A lone pair orbital for O4 with 1.8946 electrons

-With core pairs on: O 1 C 2 O 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 the second lone pair donor orbital, 9, for O1 with the antibonding acceptor orbital, 77, for C2-O4 is 120. kJ/mol.

The interaction of lone pair donor orbital, 10, for C2 with the antibonding acceptor orbital, 76, for O1-H3 is 22.7 kJ/mol.

The interaction of the second lone pair donor orbital, 12, for O4 with the antibonding acceptor orbital, 75, for O1-C2 is 191. 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.

16 ----- 9.531
15 ----- 8.842

14 ----- 7.027

13 ----- 5.382

12 -^-v- 1.838

11 -^-v- -0.862

10 -^-v- -1.070

9 -^-v- -3.263

8 -^-v- -3.716

7 -^-v- -4.835

6 -^-v- -7.281

5 -^-v- -17.44

4 -^-v- -19.60

3 -^-v- -261.6

2 -^-v- -499.6

1 -^-v- -500.3

## 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 = -189.2201969403 Hartrees