H3 O4 \ // O1 - C2
The multiplicity is 2.

## Atomic Charges and Dipole Moment

O1 charge=-0.451
C2 charge= 0.281
H3 charge= 0.460
O4 charge=-0.290
with a dipole moment of 2.10370 Debye

## Bond Lengths:

between O1 and C2: distance=1.341 ang___ between O1 and H3: distance=0.993 ang___
between O1 and O4: distance=2.306 ang___ between C2 and O4: distance=1.203 ang___

## Bond Angles:

for H3-O1-C2: angle=109.3 deg___ for O4-C2-O1: angle=129.9 deg___

## Bond Orders (Mulliken):

between O1 and C2: order=0.985___ between O1 and H3: order=0.821___
between O1 and O4: order=-0.076___ between C2 and O4: order=1.986___

## 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. The Lewis structure is built for the up and down electrons, separately. Note that the up and down structures can be very different.

### Hybridization in the Best Lewis Structure

#### Down Electrons

1. A bonding orbital for O1-C2 with 0.9986 electrons
__has 70.97% O 1 character in a sp2.20 hybrid
__has 29.03% C 2 character in a s0.97 p3 hybrid

2. A bonding orbital for O1-H3 with 0.9970 electrons
__has 74.15% O 1 character in a s0.77 p3 hybrid
__has 25.85% H 3 character in a s orbital

3. A bonding orbital for C2-O4 with 0.9993 electrons
__has 26.35% C 2 character in a p-pi orbital ( 99.33% p 0.67% d)
__has 73.65% O 4 character in a p-pi orbital ( 99.79% p 0.21% d)

4. A bonding orbital for C2-O4 with 0.9991 electrons
__has 32.80% C 2 character in a sp1.89 hybrid
__has 67.20% O 4 character in a sp1.64 hybrid

8. A lone pair orbital for O1 with 0.9908 electrons

9. A lone pair orbital for O1 with 0.9370 electrons
__made from a p-pi orbital ( 99.92% p 0.08% d)

10. A lone pair orbital for C2 with 0.9822 electrons

11. A lone pair orbital for O4 with 0.9932 electrons

12. A lone pair orbital for O4 with 0.9560 electrons
__made from a s0.06 p3 hybrid

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

#### Up Electrons

1. A bonding orbital for O1-C2 with 0.9971 electrons
__has 67.12% O 1 character in a sp2.37 hybrid
__has 32.88% C 2 character in a sp1.09 hybrid

2. A bonding orbital for O1-H3 with 0.9868 electrons
__has 76.86% O 1 character in a s0.96 p3 hybrid
__has 23.14% H 3 character in a s orbital

3. A bonding orbital for C2-O4 with 0.9996 electrons
__has 35.14% C 2 character in a sp0.96 hybrid
__has 64.86% O 4 character in a sp2.06 hybrid

4. A bonding orbital for C2-O4 with 0.9995 electrons
__has 19.24% C 2 character in a p-pi orbital ( 98.86% p 1.14% d)
__has 80.76% O 4 character in a p-pi orbital ( 99.81% p 0.19% d)

5. A bonding orbital for C2-O4 with 0.9981 electrons
__has 18.81% C 2 character in a p3 hybrid
__has 81.19% O 4 character in a s0.19 p3 hybrid

9. A lone pair orbital for O1 with 0.9885 electrons

10. A lone pair orbital for O1 with 0.9395 electrons
__made from a p-pi orbital ( 99.93% p 0.07% d)

11. A lone pair orbital for O4 with 0.9903 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 bonding donor orbital, 2, for O1-H3 with the third antibonding acceptor orbital, 78, for C2-O4 is 37.9 kJ/mol.

The interaction of the second lone pair donor orbital, 10, for O1 with the second antibonding acceptor orbital, 77, for C2-O4 is 124. 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. Only the spin up electron orbital energies are given.

16 ----- 3.918
15 ----- 3.621

14 ----- 0.213

13 ----- -1.904

12 -^--- -5.756

11 -^-v- -9.025

10 -^-v- -9.502

9 -^-v- -11.88

8 -^-v- -12.14

7 -^-v- -12.82

6 -^-v- -16.68

5 -^-v- -26.71

4 -^-v- -28.61

3 -^-v- -270.5

2 -^-v- -507.9

1 -^-v- -509.0

## 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 = -189.1757000175 Hartrees