## FHF-

 F3 - H1 - F2
The ion charge is -1.

## Atomic Charges and Dipole Moment

H1 charge= 0.461
F2 charge=-0.730
F3 charge=-0.730
with a dipole moment of 0.00020 Debye

## Bond Lengths:

between H1 and F2: distance=1.163 ang___ between H1 and F3: distance=1.163 ang___
between F2 and F3: distance=2.326 ang___

## Bond Angles:

for F3-H1-F2: angle=179.9 deg___

## Bond Orders (Mulliken):

between H1 and F2: order=0.443___ between H1 and F3: order=0.443___
between F2 and F3: order=-0.079___

## 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 H1-F2 with 1.9993 electrons
__has 11.46% H 1 character in a s orbital
__has 88.54% F 2 character in a s0.97 p3 hybrid

4. A lone pair orbital for F2 with 1.9996 electrons
__made from a p-pi orbital (100.00% p)

5. A lone pair orbital for F2 with 1.9996 electrons
__made from a p-pi orbital (100.00% p)

6. A lone pair orbital for F2 with 1.9983 electrons

7. A lone pair orbital for F3 with 1.9996 electrons
__made from a p-pi orbital (100.00% p)

8. A lone pair orbital for F3 with 1.9996 electrons
__made from a p-pi orbital (100.00% p)

9. A lone pair orbital for F3 with 1.9983 electrons

10. A lone pair orbital for F3 with 1.7932 electrons
__made from a s0.97 p3 hybrid

54. A antibonding orbital for H1-F2 with 0.2000 electrons
__has 88.54% H 1 character in a s orbital
__has 11.46% F 2 character in a s0.97 p3 hybrid

-With core pairs on: F 2 F 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 the third lone pair donor orbital, 9, for F3 with the antibonding acceptor orbital, 54, for H1-F2 is 65.1 kJ/mol.

The interaction of 4th lone pair donor orbital, 10, for F3 with the antibonding acceptor orbital, 54, for H1-F2 is 879. 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.

14 ----- 17.67
13 ----- 16.96 12 ----- 16.96

11 ----- 10.18

10 -^-v- -0.699 9 -^-v- -0.700

8 -^-v- -0.962

7 -^-v- -1.308 6 -^-v- -1.308

5 -^-v- -4.793

4 -^-v- -19.02
3 -^-v- -20.17

2 -^-v- -646.2 1 -^-v- -646.2