## SiH4- molecular anion

 H3 H5 \ | SI1 - H2 | H4
The ion charge is -1. The multiplicity is 2.

## Atomic Charges and Dipole Moment

SI1 charge=-0.107
H2 charge=-0.129
H3 charge=-0.124
H4 charge=-0.319
H5 charge=-0.318
with a dipole moment of 1.54775 Debye

## Bond Lengths:

between SI1 and H2: distance=1.546 ang___ between SI1 and H3: distance=1.546 ang___
between SI1 and H4: distance=1.659 ang___ between SI1 and H5: distance=1.656 ang___

## Bond Angles:

for H3-SI1-H2: angle=103.3 deg___ for H4-SI1-H2: angle=92.78 deg___
for H5-SI1-H2: angle=92.96 deg___

## Bond Orders (Mulliken):

between SI1 and H2: order=0.880___ between SI1 and H3: order=0.880___
between SI1 and H4: order=0.714___ between SI1 and H5: order=0.715___

## 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. The Lewis structure is built for the up and down electrons, separately. Note that the up and down structures can be very different.

### Hybridization in the Best Lewis Structure

#### Down Electrons

1. A bonding orbital for Si1-H2 with 0.9710 electrons
__has 37.05% Si 1 character in a s0.88 p3 d0.18 hybrid
__has 62.95% H 2 character in a s orbital

2. A bonding orbital for Si1-H3 with 0.9710 electrons
__has 37.05% Si 1 character in a s0.88 p3 d0.18 hybrid
__has 62.95% H 3 character in a s orbital

3. A bonding orbital for Si1-H4 with 0.9406 electrons
__has 19.17% Si 1 character in a s0.59 p3 d0.56 hybrid
__has 80.83% H 4 character in a s orbital

4. A bonding orbital for Si1-H5 with 0.9404 electrons
__has 19.28% Si 1 character in a s0.59 p3 d0.56 hybrid
__has 80.72% H 5 character in a s orbital

10. A lone pair orbital for Si1 with 0.9922 electrons
__made from a sp1.30 hybrid

-With core pairs on:Si 1 Si 1 Si 1 Si 1 Si 1 -

#### Up Electrons

1. A bonding orbital for Si1-H2 with 0.9930 electrons
__has 34.73% Si 1 character in a s0.68 p3 hybrid
__has 65.27% H 2 character in a s orbital

2. A bonding orbital for Si1-H3 with 0.9930 electrons
__has 34.73% Si 1 character in a s0.68 p3 hybrid
__has 65.27% H 3 character in a s orbital

3. A bonding orbital for Si1-H4 with 0.9903 electrons
__has 45.10% Si 1 character in a sp2.14 hybrid
__has 54.90% H 4 character in a s orbital

4. A bonding orbital for Si1-H5 with 0.9904 electrons
__has 45.04% Si 1 character in a sp2.13 hybrid
__has 54.96% H 5 character in a s orbital

-With core pairs on:Si 1 Si 1 Si 1 Si 1 Si 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.

## 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. Only the spin up electron orbital energies are given.

14 ----- 8.579

13 ----- 7.620
12 ----- 7.538

11 ----- 5.765

10 -^--- 2.884

9 -^-v- -0.779

8 -^-v- -1.999

7 -^-v- -2.315

6 -^-v- -6.683

5 -^-v- -87.60
4 -^-v- -87.62
3 -^-v- -87.63

2 -^-v- -129.9

1 -^-v- -1765.

## 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 = -291.8530862790 Hartrees

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