## formic acid, HCOOH, trans isomer

 O3 || C1 H2 / \ / H4 O5
Tell me about the atomic charges, dipole moment, bond lengths, angles, bond orders,
molecular orbital energies, or total energy.
Tell me about the best Lewis structure.

## Atomic Charges and Dipole Moment

C1 charge= 0.527
H2 charge= 0.445
O3 charge=-0.489
H4 charge= 0.077
O5 charge=-0.561
with a dipole moment of 1.53032 Debye

## Bond Lengths:

between C1 and O3: distance=1.217 ang___ between C1 and H4: distance=1.110 ang___
between C1 and O5: distance=1.365 ang___ between H2 and O5: distance=0.986 ang___
between O3 and O5: distance=2.288 ang___ between H4 and O5: distance=2.028 ang___

## Bond Angles:

for O3-C1-H2: angle=94.92 deg___ for H4-C1-H2: angle=139.4 deg___
for O5-C1-H2: angle=29.77 deg___

## Bond Orders (Mulliken):

between C1 and O3: order=1.872___ between C1 and H4: order=0.992___
between C1 and O5: order=1.049___ between H2 and O5: order=0.835___
between O3 and O5: order=-0.101___ between H4 and O5: order=-0.065___

## 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-O3 with 1.9988 electrons
__has 26.81% C 1 character in a p-pi orbital ( 99.32% p 0.68% d)
__has 73.19% O 3 character in a p-pi orbital ( 99.81% p 0.19% d)

2. A bonding orbital for C1-O3 with 1.9986 electrons
__has 35.52% C 1 character in a sp1.72 hybrid
__has 64.48% O 3 character in a sp1.59 hybrid

3. A bonding orbital for C1-H4 with 1.9865 electrons
__has 57.21% C 1 character in a sp1.91 hybrid
__has 42.79% H 4 character in a s orbital

4. A bonding orbital for C1-O5 with 1.9966 electrons
__has 32.26% C 1 character in a sp2.35 hybrid
__has 67.74% O 5 character in a sp2.28 hybrid

5. A bonding orbital for H2-O5 with 1.9899 electrons
__has 24.86% H 2 character in a s orbital
__has 75.14% O 5 character in a s0.85 p3 hybrid

9. A lone pair orbital for O3 with 1.9829 electrons
__made from a sp0.61 hybrid

10. A lone pair orbital for O3 with 1.8788 electrons
__made from a p3 hybrid

11. A lone pair orbital for O5 with 1.9823 electrons
__made from a sp1.10 hybrid

12. A lone pair orbital for O5 with 1.8754 electrons
__made from a p-pi orbital ( 99.93% p 0.07% d)

80. A antibonding orbital for C1-O3 with 0.1191 electrons
__has 73.19% C 1 character in a p-pi orbital ( 99.32% p 0.68% d)
__has 26.81% O 3 character in a p-pi orbital ( 99.81% p 0.19% d)

-With core pairs on: C 1 O 3 O 5 -

#### 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, 10, for O3 with the antibonding acceptor orbital, 82, for C1-H4 is 112. kJ/mol.

The interaction of the second lone pair donor orbital, 10, for O3 with the antibonding acceptor orbital, 83, for C1-O5 is 173. kJ/mol.

The interaction of lone pair donor orbital, 11, for O5 with the second antibonding acceptor orbital, 81, for C1-O3 is 35.3 kJ/mol.

The interaction of the second lone pair donor orbital, 12, for O5 with the antibonding acceptor orbital, 80, for C1-O3 is 240. 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 ----- 3.324

15 ----- 2.279

14 ----- 0.557

13 ----- -1.885

12 -^-v- -7.091

11 -^-v- -8.361

10 -^-v- -10.05

9 -^-v- -11.30

8 -^-v- -12.05

7 -^-v- -12.98

6 -^-v- -16.70

5 -^-v- -25.71

4 -^-v- -27.91

3 -^-v- -270.2

2 -^-v- -506.8

1 -^-v- -508.3

## 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 = -189.8427254414 Hartrees

Note: The cis-formic acid isomer is higher in energy.

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