H2SO3, Formally sulfurous acid*

H4
|
O3
|
H6 - O1 - S2
\\
O5
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=-0.521
S2 charge= 0.653
O3 charge=-0.541
H4 charge= 0.431
O5 charge=-0.450
H6 charge= 0.427
with a dipole moment of 1.61541 Debye

Bond Lengths:

between O1 and S2: distance=1.690 ang___ between O1 and H6: distance=0.987 ang___
between S2 and O3: distance=1.695 ang___ between S2 and O5: distance=1.496 ang___
between O3 and H4: distance=0.986 ang___

Bond Angles:

for O3-S2-O1: angle=100.1 deg___ for H4-O3-S2: angle=107.1 deg___
for O5-S2-O1: angle=107.0 deg___ for H6-O1-S2: angle=108.4 deg___

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Bond Orders (Mulliken):

between O1 and S2: order=0.789___ between O1 and H6: order=0.836___
between S2 and O3: order=0.816___ between S2 and O5: order=1.503___
between O3 and H4: order=0.836___

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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. 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 O1-S2 with 1.9885 electrons
__has 70.26% O 1 character in a s0.64 p3 hybrid
__has 29.74% S 2 character in a s0.39 p3 d0.09 hybrid

2. A bonding orbital for O1-H6 with 1.9942 electrons
__has 75.06% O 1 character in a s0.95 p3 hybrid
__has 24.94% H 6 character in a s orbital

3. A bonding orbital for S2-O3 with 1.9877 electrons
__has 29.75% S 2 character in a s0.39 p3 d0.09 hybrid
__has 70.25% O 3 character in a s0.63 p3 hybrid

4. A bonding orbital for S2-O5 with 1.9864 electrons
__has 35.93% S 2 character in a s0.77 p3 d0.07 hybrid
__has 64.07% O 5 character in a s0.78 p3 hybrid

5. A bonding orbital for O3-H4 with 1.9939 electrons
__has 75.22% O 3 character in a s0.97 p3 hybrid
__has 24.78% H 4 character in a s orbital

14. A lone pair orbital for O1 with 1.9874 electrons
__made from a sp0.71 hybrid

15. A lone pair orbital for O1 with 1.9566 electrons
__made from a p3 hybrid

16. A lone pair orbital for S2 with 1.9888 electrons
__made from a sp0.69 hybrid

17. A lone pair orbital for O3 with 1.9885 electrons
__made from a sp0.72 hybrid

18. A lone pair orbital for O3 with 1.9607 electrons
__made from a p3 hybrid

19. A lone pair orbital for O5 with 1.9946 electrons
__made from a sp0.27 hybrid

20. A lone pair orbital for O5 with 1.8813 electrons
__made from a p3 hybrid

21. A lone pair orbital for O5 with 1.8260 electrons
__made from a p3 hybrid

111. A antibonding orbital for O1-S2 with 0.1488 electrons
__has 29.74% O 1 character in a s0.64 p3 hybrid
__has 70.26% S 2 character in a s0.39 p3 d0.09 hybrid

113. A antibonding orbital for S2-O3 with 0.1466 electrons
__has 70.25% S 2 character in a s0.39 p3 d0.09 hybrid
__has 29.75% O 3 character in a s0.63 p3 hybrid

-With core pairs on: O 1 S 2 S 2 S 2 S 2 S 2 O 3 O 5 -

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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 the second lone pair donor orbital, 15, for O1 with the antibonding acceptor orbital, 113, for S2-O3 is 47.4 kJ/mol.

The interaction of the second lone pair donor orbital, 18, for O3 with the antibonding acceptor orbital, 111, for O1-S2 is 51.6 kJ/mol.

The interaction of the second lone pair donor orbital, 20, for O5 with the antibonding acceptor orbital, 111, for O1-S2 is 66.0 kJ/mol.

The interaction of the second lone pair donor orbital, 20, for O5 with the antibonding acceptor orbital, 113, for S2-O3 is 75.7 kJ/mol.

The interaction of the third lone pair donor orbital, 21, for O5 with the antibonding acceptor orbital, 111, for O1-S2 is 122. kJ/mol.

The interaction of the third lone pair donor orbital, 21, for O5 with the antibonding acceptor orbital, 113, for S2-O3 is 109. 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.

25 ----- 0.440

24 ----- 0.115


23 ----- -1.346

22 ----- -1.674


21 -^-v- -7.441

20 -^-v- -7.855

19 -^-v- -8.617

18 -^-v- -9.329

17 -^-v- -9.758


16 -^-v- -11.19

15 -^-v- -12.07

14 -^-v- -12.84


13 -^-v- -14.47


12 -^-v- -17.86


11 -^-v- -25.45

10 -^-v- -25.96


9 -^-v- -28.25


8 -^-v- -159.4

7 -^-v- -159.7
6 -^-v- -159.7


5 -^-v- -212.5


4 -^-v- -507.1

3 -^-v- -508.0
2 -^-v- -508.1


1 -^-v- -2392.

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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 = -625.1749626936 Hartrees

* Free sulfurous acid is not known. Rather, solutions of sulfurous acid are better characterized as a clathrate of SO2, SO2.. 7 H2O. See F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry, Wiley, New York, NY., 1966. 2nd Ed. Section 21-13. Top of page.

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