## Formamide anion*, HCONH-

 O3 \ C1 - N2 / | H4 H5
The ion charge is -1.

## Atomic Charges and Dipole Moment

C1 charge= 0.681
N2 charge=-1.013
O3 charge=-0.760
H4 charge=-0.167
H5 charge= 0.260
with a dipole moment of 2.71675 Debye

## Bond Lengths:

between C1 and N2: distance=1.338 ang___ between C1 and O3: distance=1.274 ang___
between C1 and H4: distance=1.145 ang___ between C1 and H5: distance=1.911 ang___
between N2 and O3: distance=2.343 ang___ between N2 and H4: distance=2.118 ang___
between N2 and H5: distance=1.035 ang___

## Bond Angles:

for O3-C1-N2: angle=127.5 deg___ for H4-C1-N2: angle=116.8 deg___
for H5-N2-C1: angle=106.6 deg___

## Bond Orders (Mulliken):

between C1 and N2: order=1.534___ between C1 and O3: order=1.525___
between C1 and H4: order=1.067___ between C1 and H5: order=0.058___
between N2 and O3: order=-0.246___ between N2 and H4: order=-0.108___
between N2 and H5: order=0.872___

## 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-N2 with 1.9964 electrons
__has 42.09% C 1 character in a sp1.59 hybrid
__has 57.91% N 2 character in a sp1.82 hybrid

2. A bonding orbital for C1-N2 with 1.9952 electrons
__has 24.65% C 1 character in a p-pi orbital ( 99.60% p 0.40% d)
__has 75.35% N 2 character in a p-pi orbital ( 99.85% p 0.15% d)

3. A bonding orbital for C1-O3 with 1.9968 electrons
__has 36.00% C 1 character in a sp1.89 hybrid
__has 64.00% O 3 character in a sp1.71 hybrid

4. A bonding orbital for C1-H4 with 1.9916 electrons
__has 51.96% C 1 character in a sp2.57 hybrid
__has 48.04% H 4 character in a s orbital

5. A bonding orbital for N2-H5 with 1.9776 electrons
__has 63.59% N 2 character in a s0.78 p3 hybrid
__has 36.41% H 5 character in a s orbital

9. A lone pair orbital for N2 with 1.9613 electrons

10. A lone pair orbital for O3 with 1.9809 electrons

11. A lone pair orbital for O3 with 1.9051 electrons

12. A lone pair orbital for O3 with 1.6922 electrons
__made from a p-pi orbital ( 99.90% p 0.10% d)

81. A antibonding orbital for C1-N2 with 0.2975 electrons
__has 75.35% C 1 character in a p-pi orbital ( 99.60% p 0.40% d)
__has 24.65% N 2 character in a p-pi orbital ( 99.85% p 0.15% d)

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

#### 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, 5, for N2-H5 with the antibonding acceptor orbital, 82, for C1-O3 is 48.7 kJ/mol.

The interaction of lone pair donor orbital, 9, for N2 with the antibonding acceptor orbital, 83, for C1-H4 is 50.7 kJ/mol.

The interaction of the second lone pair donor orbital, 11, for O3 with the antibonding acceptor orbital, 80, for C1-N2 is 87.2 kJ/mol.

The interaction of the second lone pair donor orbital, 11, for O3 with the antibonding acceptor orbital, 83, for C1-H4 is 122. kJ/mol.

The interaction of the third lone pair donor orbital, 12, for O3 with the second antibonding acceptor orbital, 81, for C1-N2 is 619. 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 ----- 9.319

15 ----- 7.923

14 ----- 6.955

13 ----- 5.923

12 -^-v- 0.831

11 -^-v- 0.663

10 -^-v- -0.226

9 -^-v- -2.923

8 -^-v- -3.413

7 -^-v- -5.878

6 -^-v- -6.979

5 -^-v- -14.57

4 -^-v- -18.23

3 -^-v- -262.0

2 -^-v- -369.9

1 -^-v- -498.8

## 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 = -169.3713397257 Hartrees

* For an interesting discussion of this ion see C&ENews, 1996, Sept. 30, p 37.