## SiF4

 F3 \ Si1 - F2 / | F4 F5
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

SI1 charge= 1.352
F2 charge=-0.338
F3 charge=-0.338
F4 charge=-0.338
F5 charge=-0.337
with a dipole moment of 0.01397 Debye

## Bond Lengths:

between SI1 and F2: distance=1.601 ang___ between SI1 and F3: distance=1.601 ang___
between SI1 and F4: distance=1.602 ang___ between SI1 and F5: distance=1.602 ang___

## Bond Angles:

for F3-SI1-F2: angle=109.7 deg___ for F4-SI1-F2: angle=109.2 deg___
for F5-SI1-F2: angle=109.3 deg___

## Bond Orders (Mulliken):

between SI1 and F2: order=1.029___ between SI1 and F3: order=1.029___
between SI1 and F4: order=1.029___ between SI1 and F5: order=1.029___

## 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 Si1-F2 with 1.9885 electrons
__has 12.55% Si 1 character in a sp2.87 d0.12 hybrid
__has 87.45% F 2 character in a sp2.12 hybrid

2. A bonding orbital for Si1-F3 with 1.9885 electrons
__has 12.55% Si 1 character in a sp2.87 d0.12 hybrid
__has 87.45% F 3 character in a sp2.12 hybrid

3. A bonding orbital for Si1-F4 with 1.9885 electrons
__has 12.56% Si 1 character in a sp2.87 d0.12 hybrid
__has 87.44% F 4 character in a sp2.12 hybrid

4. A bonding orbital for Si1-F5 with 1.9885 electrons
__has 12.56% Si 1 character in a sp2.87 d0.12 hybrid
__has 87.44% F 5 character in a sp2.12 hybrid

14. A lone pair orbital for F2 with 1.9899 electrons

15. A lone pair orbital for F2 with 1.9640 electrons
__made from a p-pi orbital ( 99.96% p)

16. A lone pair orbital for F2 with 1.9637 electrons
__made from a p-pi orbital ( 99.96% p)

17. A lone pair orbital for F3 with 1.9899 electrons

18. A lone pair orbital for F3 with 1.9640 electrons
__made from a p-pi orbital ( 99.96% p)

19. A lone pair orbital for F3 with 1.9637 electrons
__made from a p-pi orbital ( 99.96% p)

20. A lone pair orbital for F4 with 1.9899 electrons

21. A lone pair orbital for F4 with 1.9640 electrons
__made from a p-pi orbital ( 99.96% p)

22. A lone pair orbital for F4 with 1.9637 electrons
__made from a p-pi orbital ( 99.96% p)

23. A lone pair orbital for F5 with 1.9899 electrons

24. A lone pair orbital for F5 with 1.9640 electrons
__made from a p-pi orbital ( 99.96% p)

25. A lone pair orbital for F5 with 1.9637 electrons
__made from a p-pi orbital ( 99.96% p)

-With core pairs on:Si 1 Si 1 Si 1 Si 1 Si 1 F 2 F 3 F 4 F 5 -

#### 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 second lone pair donor orbital, 15, for F2 with the antibonding acceptor orbital, 126, for Si1-F4 is 32.9 kJ/mol.

The interaction of the second lone pair donor orbital, 15, for F2 with the antibonding acceptor orbital, 127, for Si1-F5 is 30.7 kJ/mol.

The interaction of the third lone pair donor orbital, 16, for F2 with the antibonding acceptor orbital, 125, for Si1-F3 is 42.5 kJ/mol.

The interaction of the second lone pair donor orbital, 18, for F3 with the antibonding acceptor orbital, 126, for Si1-F4 is 31.1 kJ/mol.

The interaction of the second lone pair donor orbital, 18, for F3 with the antibonding acceptor orbital, 127, for Si1-F5 is 32.5 kJ/mol.

The interaction of the third lone pair donor orbital, 19, for F3 with the antibonding acceptor orbital, 124, for Si1-F2 is 42.5 kJ/mol.

The interaction of the second lone pair donor orbital, 21, for F4 with the antibonding acceptor orbital, 124, for Si1-F2 is 32.3 kJ/mol.

The interaction of the second lone pair donor orbital, 21, for F4 with the antibonding acceptor orbital, 125, for Si1-F3 is 31.2 kJ/mol.

The interaction of the third lone pair donor orbital, 22, for F4 with the antibonding acceptor orbital, 127, for Si1-F5 is 42.4 kJ/mol.

The interaction of the second lone pair donor orbital, 24, for F5 with the antibonding acceptor orbital, 124, for Si1-F2 is 30.6 kJ/mol.

The interaction of the second lone pair donor orbital, 24, for F5 with the antibonding acceptor orbital, 125, for Si1-F3 is 32.8 kJ/mol.

The interaction of the third lone pair donor orbital, 25, for F5 with the antibonding acceptor orbital, 126, for Si1-F4 is 42.4 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.

29 ----- 0.782
28 ----- 0.763
27 ----- 0.731

26 ----- -1.654

25 -^-v- -10.92 24 -^-v- -10.92 23 -^-v- -10.93

22 -^-v- -11.88 21 -^-v- -11.88 20 -^-v- -11.88

19 -^-v- -12.02
18 -^-v- -12.03

17 -^-v- -13.61 16 -^-v- -13.61 15 -^-v- -13.62

14 -^-v- -15.55

13 -^-v- -30.56 12 -^-v- -30.56
11 -^-v- -30.57

10 -^-v- -31.47

9 -^-v- -98.51 8 -^-v- -98.52 7 -^-v- -98.53

6 -^-v- -140.8

5 -^-v- -657.0 4 -^-v- -657.0 3 -^-v- -657.0 2 -^-v- -657.0

1 -^-v- -1776.

## 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 = -689.3090808943 Hartrees