## AlH4+

 H3 \ Al - H4 / \ | H5 H2
The ion charge is 1.

## Atomic Charges and Dipole Moment

AL1 charge= 1.137
H2 charge= 0.085
H3 charge=-0.153
H4 charge= 0.084
H5 charge=-0.154
with a dipole moment of 3.26529 Debye

## Bond Lengths:

between AL1 and H2: distance=2.075 ang___ between AL1 and H3: distance=1.571 ang___
between AL1 and H4: distance=2.073 ang___ between AL1 and H5: distance=1.571 ang___
between H2 and H4: distance=0.776 ang___

## Bond Angles:

for H3-AL1-H2: angle=108.7 deg___ for H4-AL1-H2: angle=21.56 deg___
for H5-AL1-H2: angle=87.19 deg___

## Bond Orders (Mulliken):

between AL1 and H2: order=0.148___ between AL1 and H3: order=0.990___
between AL1 and H4: order=0.148___ between AL1 and H5: order=0.990___
between H2 and H4: order=0.833___

## 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 Al1-H3 with 1.9794 electrons
__has 33.92% Al 1 character in a sp1.02 hybrid
__has 66.08% H 3 character in a s orbital

2. A bonding orbital for Al1-H5 with 1.9794 electrons
__has 33.91% Al 1 character in a sp1.02 hybrid
__has 66.09% H 5 character in a s orbital

3. A bonding orbital for H2-H4 with 1.8943 electrons
__has 49.96% H 2 character in a s orbital
__has 50.04% H 4 character in a s orbital

-With core pairs on:Al 1 Al 1 Al 1 Al 1 Al 1 -

#### 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, 1, for Al1-H3 with the antibonding acceptor orbital, 54, for Al1-H5 is 49.1 kJ/mol.

The interaction of bonding donor orbital, 2, for Al1-H5 with the antibonding acceptor orbital, 53, for Al1-H3 is 49.1 kJ/mol.

The interaction of bonding donor orbital, 1, for Al1-H3 with the antibonding acceptor orbital, 55, for H2-H4 is 10.8 kJ/mol.

The interaction of bonding donor orbital, 2, for Al1-H5 with the antibonding acceptor orbital, 55, for H2-H4 is 10.7 kJ/mol.

The interaction of bonding donor orbital, 3, for H2-H4 with the lone pair acceptor orbital, 9, for Al1 is 195. kJ/mol.

The interaction of bonding donor orbital, 3, for H2-H4 with the antibonding acceptor orbital, 53, for Al1-H3 is 18.9 kJ/mol.

The interaction of bonding donor orbital, 3, for H2-H4 with the antibonding acceptor orbital, 54, for Al1-H5 is 18.9 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.

12 ----- -5.856

11 ----- -7.364

10 ----- -7.627

9 ----- -9.003

8 -^-v- -14.41

7 -^-v- -16.04

6 -^-v- -19.34

5 -^-v- -76.64

4 -^-v- -77.27
3 -^-v- -77.35

2 -^-v- -114.3

1 -^-v- -1508.

## 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 = -244.5048629367 Hartrees