## cyclic SiO2, see note*

 SI3 / | O1 - O2
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

O1 charge=-0.258
O2 charge=-0.258
SI3 charge= 0.516
with a dipole moment of 2.97323 Debye

## Bond Lengths:

between O1 and O2: distance=1.603 ang___ between O1 and SI3: distance=1.696 ang___
between O2 and SI3: distance=1.697 ang___

## Bond Angles:

for SI3-O1-O2: angle=61.85 deg___

## Bond Orders (Mulliken):

between O1 and O2: order=0.791___ between O1 and SI3: order=0.799___
between O2 and SI3: order=0.796___

## 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 O1-O2 with 1.9892 electrons
__has 50.05% O 1 character in a s0.11 p3 hybrid
__has 49.95% O 2 character in a s0.11 p3 hybrid

2. A bonding orbital for O1-Si3 with 1.9887 electrons
__has 88.14% O 1 character in a s0.97 p3 hybrid
__has 11.86% Si 3 character in a s0.32 p3 d0.13 hybrid

3. A bonding orbital for O2-Si3 with 1.9884 electrons
__has 88.14% O 2 character in a s0.96 p3 hybrid
__has 11.86% Si 3 character in a s0.32 p3 d0.13 hybrid

11. A lone pair orbital for O1 with 1.9927 electrons

12. A lone pair orbital for O1 with 1.9415 electrons
__made from a p-pi orbital ( 99.94% p 0.06% d)

13. A lone pair orbital for O2 with 1.9927 electrons

14. A lone pair orbital for O2 with 1.9421 electrons
__made from a p-pi orbital ( 99.94% p 0.06% d)

15. A lone pair orbital for Si3 with 1.9981 electrons

16. A lone pair orbital for Si3 with 0.1077 electrons
__made from a p-pi orbital ( 92.24% p 7.76% d)

-With core pairs on: O 1 O 2 Si 3 Si 3 Si 3 Si 3 Si 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, 2, for O1-Si3 with the antibonding acceptor orbital, 77, for O1-O2 is 21.8 kJ/mol.

The interaction of bonding donor orbital, 3, for O2-Si3 with the antibonding acceptor orbital, 77, for O1-O2 is 22.5 kJ/mol.

The interaction of the second lone pair donor orbital, 12, for O1 with the second lone pair acceptor orbital, 16, for Si3 is 120. kJ/mol.

The interaction of the second lone pair donor orbital, 14, for O2 with the second lone pair acceptor orbital, 16, for Si3 is 119. 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.

19 ----- 0.426

18 ----- -1.798

17 ----- -3.409

16 ----- -3.757

15 -^-v- -6.570

14 -^-v- -7.924

13 -^-v- -8.551

12 -^-v- -10.19

11 -^-v- -11.32

10 -^-v- -12.64

9 -^-v- -21.25

8 -^-v- -27.17

7 -^-v- -95.93

6 -^-v- -96.07

5 -^-v- -96.23

4 -^-v- -138.4

3 -^-v- -508.2
2 -^-v- -508.2

1 -^-v- -1774.

## 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 = -439.9568261819 Hartrees

* Note: linear SiO2 is much lower in energy.