## C2H3O2-, hydroxylacetaldehyde anion, formylmethoxide ion

 O3 H6 | / H4 - C1 - C2 / \\ H5 O7
The ion charge is -1.

## Atomic Charges and Dipole Moment

C1 charge= 0.399
C2 charge= 0.175
O3 charge=-0.784
H4 charge=-0.158
H5 charge=-0.076
H6 charge= 0.007
O7 charge=-0.562
with a dipole moment of 3.86131 Debye

## Bond Lengths:

between C1 and C2: distance=1.514 ang___ between C1 and O3: distance=1.384 ang___
between C1 and H4: distance=1.138 ang___ between C1 and H5: distance=1.128 ang___
between C2 and H5: distance=2.169 ang___ between C2 and H6: distance=1.125 ang___
between C2 and O7: distance=1.251 ang___

## Bond Angles:

for O3-C1-C2: angle=96.66 deg___ for H4-C1-C2: angle=111.7 deg___
for H5-C1-C2: angle=109.5 deg___ for H6-C2-C1: angle=111.7 deg___
for O7-C2-C1: angle=127.0 deg___

## Bond Orders (Mulliken):

between C1 and C2: order=0.893___ between C1 and O3: order=1.012___
between C1 and H4: order=0.930___ between C1 and H5: order=0.984___
between C2 and H5: order=-0.052___ between C2 and H6: order=1.010___
between C2 and O7: order=1.700___

## 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 1.9911 electrons
__has 48.63% C 1 character in a s0.97 p3 hybrid
__has 51.37% C 2 character in a sp1.67 hybrid

2. A bonding orbital for C1-O3 with 1.9812 electrons
__has 40.89% C 1 character in a sp2.56 hybrid
__has 59.11% O 3 character in a sp2.81 hybrid

3. A bonding orbital for C1-H4 with 1.9871 electrons
__has 54.44% C 1 character in a s0.91 p3 hybrid
__has 45.56% H 4 character in a s orbital

4. A bonding orbital for C1-H5 with 1.9884 electrons
__has 55.70% C 1 character in a s0.97 p3 hybrid
__has 44.30% H 5 character in a s orbital

5. A bonding orbital for C2-H6 with 1.9884 electrons
__has 55.07% C 2 character in a sp2.38 hybrid
__has 44.93% H 6 character in a s orbital

6. A bonding orbital for C2-O7 with 1.9967 electrons
__has 34.02% C 2 character in a sp2.19 hybrid
__has 65.98% O 7 character in a sp1.74 hybrid

7. A bonding orbital for C2-O7 with 1.9940 electrons
__has 25.70% C 2 character in a s0.08 p3 hybrid
__has 74.30% O 7 character in a s0.08 p3 hybrid

12. A lone pair orbital for O3 with 1.9911 electrons

13. A lone pair orbital for O3 with 1.9220 electrons

14. A lone pair orbital for O3 with 1.8802 electrons

15. A lone pair orbital for O7 with 1.9830 electrons

16. A lone pair orbital for O7 with 1.9171 electrons

-With core pairs on: C 1 C 2 O 3 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 bonding donor orbital, 2, for C1-O3 with the second antibonding acceptor orbital, 114, for C2-O7 is 22.0 kJ/mol.

The interaction of the second lone pair donor orbital, 13, for O3 with the antibonding acceptor orbital, 110, for C1-H4 is 74.0 kJ/mol.

The interaction of the second lone pair donor orbital, 13, for O3 with the antibonding acceptor orbital, 111, for C1-H5 is 71.2 kJ/mol.

The interaction of the third lone pair donor orbital, 14, for O3 with the antibonding acceptor orbital, 108, for C1-C2 is 49.7 kJ/mol.

The interaction of the third lone pair donor orbital, 14, for O3 with the antibonding acceptor orbital, 110, for C1-H4 is 21.9 kJ/mol.

The interaction of the third lone pair donor orbital, 14, for O3 with the second antibonding acceptor orbital, 114, for C2-O7 is 57.9 kJ/mol.

The interaction of the second lone pair donor orbital, 16, for O7 with the antibonding acceptor orbital, 108, for C1-C2 is 85.1 kJ/mol.

The interaction of the second lone pair donor orbital, 16, for O7 with the antibonding acceptor orbital, 112, for C2-H6 is 116. 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.

20 ----- 7.673
19 ----- 7.397

18 ----- 6.614

17 ----- 3.668

16 -^-v- 1.030

15 -^-v- 0.771

14 -^-v- -0.624

13 -^-v- -2.961

12 -^-v- -3.721

11 -^-v- -4.284

10 -^-v- -5.163

9 -^-v- -5.931

8 -^-v- -8.327

7 -^-v- -10.78

6 -^-v- -17.24

5 -^-v- -19.88

4 -^-v- -261.7

3 -^-v- -262.9

2 -^-v- -498.6

1 -^-v- -500.6

## 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 = -228.5423930142 Hartrees