Lithium aluminum hydride, LiAlH4

H3
\
LI1 - AL2 - H6
/
H4

Atom Overlaps: H3~H5;
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

LI1 charge= 0.795
AL2 charge= 0.877
H3 charge=-0.466
H4 charge=-0.463
H5 charge=-0.464
H6 charge=-0.278
with a dipole moment of 5.37597 Debye

Bond Lengths:

between LI1 and AL2: distance=2.355 ang___ between LI1 and H3: distance=2.060 ang___
between LI1 and H4: distance=2.069 ang___ between LI1 and H5: distance=2.067 ang___
between AL2 and H3: distance=1.686 ang___ between AL2 and H4: distance=1.684 ang___
between AL2 and H5: distance=1.684 ang___ between AL2 and H6: distance=1.597 ang___

Bond Angles:

for H3-LI1-AL2: angle=44.27 deg___ for H4-LI1-AL2: angle=44.15 deg___
for H5-LI1-AL2: angle=44.17 deg___ for H6-AL2-LI1: angle=179.5 deg___

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Bond Orders (Mulliken):

between LI1 and AL2: order=0.264___ between LI1 and H3: order=0.206___
between LI1 and H4: order=0.202___ between LI1 and H5: order=0.203___
between AL2 and H3: order=0.655___ between AL2 and H4: order=0.660___
between AL2 and H5: order=0.659___ between AL2 and H6: order=0.928___

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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.

Hybridization in the Best Lewis Structure

1. A bonding orbital for Al2-H3 with 1.9655 electrons
__has 25.95% Al 2 character in a s0.77 p3 d0.06 hybrid
__has 74.05% H 3 character in a s orbital

2. A bonding orbital for Al2-H4 with 1.9658 electrons
__has 26.04% Al 2 character in a s0.78 p3 d0.06 hybrid
__has 73.96% H 4 character in a s orbital

3. A bonding orbital for Al2-H5 with 1.9657 electrons
__has 26.03% Al 2 character in a s0.78 p3 d0.06 hybrid
__has 73.97% H 5 character in a s orbital

4. A bonding orbital for Al2-H6 with 1.9968 electrons
__has 32.51% Al 2 character in a sp1.58 hybrid
__has 67.49% H 6 character in a s orbital

-With core pairs on:Li 1 Al 2 Al 2 Al 2 Al 2 Al 2 -

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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 Al2-H3 with the lone pair acceptor orbital, 11, for Li1 is 27.4 kJ/mol.

The interaction of bonding donor orbital, 2, for Al2-H4 with the lone pair acceptor orbital, 11, for Li1 is 26.0 kJ/mol.

The interaction of bonding donor orbital, 3, for Al2-H5 with the lone pair acceptor orbital, 11, for Li1 is 26.3 kJ/mol.

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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 ----- 0.750

13 ----- 0.305
12 ----- 0.300


11 ----- -1.870


10 -^-v- -6.437 9 -^-v- -6.443

8 -^-v- -7.009


7 -^-v- -10.21


6 -^-v- -51.93


5 -^-v- -67.52

4 -^-v- -67.70 3 -^-v- -67.70


2 -^-v- -104.8


1 -^-v- -1498.

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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 = -252.3555326300 Hartrees

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