## peroxodicarbonate dianion, O2COOCO22-

 O4 \ C3 = O5 / O1 - O2 / O7 - C6 \\ O8
The ion charge is -2.

## Atomic Charges and Dipole Moment

O1 charge=-0.341
O2 charge=-0.344
C3 charge= 0.932
O4 charge=-0.782
O5 charge=-0.806
C6 charge= 0.929
O7 charge=-0.805
O8 charge=-0.780
with a dipole moment of 7.41619 Debye

## Bond Lengths:

between O1 and O2: distance=1.584 ang___ between O1 and C6: distance=1.433 ang___
between O1 and O7: distance=2.184 ang___ between O1 and O8: distance=2.350 ang___
between O2 and C3: distance=1.433 ang___ between O2 and O4: distance=2.350 ang___
between O2 and O5: distance=2.184 ang___ between C3 and O4: distance=1.255 ang___
between C3 and O5: distance=1.276 ang___ between O4 and O5: distance=2.302 ang___
between C6 and O7: distance=1.276 ang___ between C6 and O8: distance=1.255 ang___
between O7 and O8: distance=2.302 ang___

## Bond Angles:

for C3-O2-O1: angle=112.2 deg___ for O4-C3-O2: angle=121.7 deg___
for O5-C3-O2: angle=107.3 deg___ for C6-O1-O2: angle=112.2 deg___
for O7-C6-O1: angle=107.3 deg___ for O8-C6-O1: angle=121.7 deg___

## Bond Orders (Mulliken):

between O1 and O2: order=0.857___ between O1 and C6: order=0.779___
between O1 and O7: order=-0.180___ between O1 and O8: order=-0.150___
between O2 and C3: order=0.779___ between O2 and O4: order=-0.151___
between O2 and O5: order=-0.180___ between C3 and O4: order=1.642___
between C3 and O5: order=1.506___ between O4 and O5: order=-0.090___
between C6 and O7: order=1.506___ between C6 and O8: order=1.642___
between O7 and O8: order=-0.090___

## 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. (This analysis was run at the DZVP level with diffuse functions instead of the TZVP level, because of the size of the calculation.)

### Hybridization in the Best Lewis Structure

1. A bonding orbital for O1-O2 with 1.9851 electrons
__has 50.00% O 1 character in a s0.29 p3 hybrid
__has 50.00% O 2 character in a s0.29 p3 hybrid

2. A bonding orbital for O1-C6 with 1.9884 electrons
__has 72.38% O 1 character in a sp2.42 hybrid
__has 27.62% C 6 character in a sp2.86 hybrid

3. A bonding orbital for O2-C3 with 1.9884 electrons
__has 72.38% O 2 character in a sp2.42 hybrid
__has 27.62% C 3 character in a sp2.86 hybrid

4. A bonding orbital for C3-O4 with 1.9979 electrons
__has 18.25% C 3 character in a p-pi orbital ( 99.21% p 0.79% d)
__has 81.75% O 4 character in a p-pi orbital ( 99.76% p 0.24% d)

5. A bonding orbital for C3-O4 with 1.9944 electrons
__has 34.08% C 3 character in a sp1.62 hybrid
__has 65.92% O 4 character in a sp1.79 hybrid

6. A bonding orbital for C3-O5 with 1.9893 electrons
__has 34.18% C 3 character in a sp1.73 hybrid
__has 65.82% O 5 character in a sp1.93 hybrid

7. A bonding orbital for C6-O7 with 1.9893 electrons
__has 34.18% C 6 character in a sp1.73 hybrid
__has 65.82% O 7 character in a sp1.93 hybrid

8. A bonding orbital for C6-O8 with 1.9979 electrons
__has 18.25% C 6 character in a p-pi orbital ( 99.21% p 0.79% d)
__has 81.75% O 8 character in a p-pi orbital ( 99.76% p 0.24% d)

9. A bonding orbital for C6-O8 with 1.9944 electrons
__has 34.08% C 6 character in a sp1.62 hybrid
__has 65.92% O 8 character in a sp1.79 hybrid

18. A lone pair orbital for O1 with 1.9866 electrons

19. A lone pair orbital for O1 with 1.9269 electrons
__made from a p-pi orbital ( 99.92% p 0.08% d)

20. A lone pair orbital for O2 with 1.9866 electrons

21. A lone pair orbital for O2 with 1.9269 electrons
__made from a p-pi orbital ( 99.92% p 0.08% d)

22. A lone pair orbital for O4 with 1.9803 electrons

23. A lone pair orbital for O4 with 1.8949 electrons

24. A lone pair orbital for O5 with 1.9814 electrons

25. A lone pair orbital for O5 with 1.8951 electrons

26. A lone pair orbital for O5 with 1.7319 electrons
__made from a p-pi orbital ( 99.79% p 0.21% d)

27. A lone pair orbital for O7 with 1.9814 electrons

28. A lone pair orbital for O7 with 1.8951 electrons

29. A lone pair orbital for O7 with 1.7319 electrons
__made from a p-pi orbital ( 99.79% p 0.21% d)

30. A lone pair orbital for O8 with 1.9803 electrons

31. A lone pair orbital for O8 with 1.8949 electrons

145. A antibonding orbital for O1-C6 with 0.1253 electrons
__has 27.62% O 1 character in a sp2.42 hybrid
__has 72.38% C 6 character in a sp2.86 hybrid

146. A antibonding orbital for O2-C3 with 0.1253 electrons
__has 27.62% O 2 character in a sp2.42 hybrid
__has 72.38% C 3 character in a sp2.86 hybrid

147. A antibonding orbital for C3-O4 with 0.3260 electrons
__has 81.75% C 3 character in a p-pi orbital ( 99.21% p 0.79% d)
__has 18.25% O 4 character in a p-pi orbital ( 99.76% p 0.24% d)

151. A antibonding orbital for C6-O8 with 0.3260 electrons
__has 81.75% C 6 character in a p-pi orbital ( 99.21% p 0.79% d)
__has 18.25% O 8 character in a p-pi orbital ( 99.76% p 0.24% d)

-With core pairs on: O 1 O 2 C 3 O 4 O 5 C 6 O 7 O 8 -

#### 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 lone pair donor orbital, 18, for O1 with the second antibonding acceptor orbital, 152, for C6-O8 is 26.2 kJ/mol.

The interaction of the second lone pair donor orbital, 19, for O1 with the antibonding acceptor orbital, 151, for C6-O8 is 152. kJ/mol.

The interaction of lone pair donor orbital, 20, for O2 with the second antibonding acceptor orbital, 148, for C3-O4 is 26.2 kJ/mol.

The interaction of the second lone pair donor orbital, 21, for O2 with the antibonding acceptor orbital, 147, for C3-O4 is 152. kJ/mol.

The interaction of lone pair donor orbital, 22, for O4 with the antibonding acceptor orbital, 149, for C3-O5 is 23.8 kJ/mol.

The interaction of the second lone pair donor orbital, 23, for O4 with the antibonding acceptor orbital, 146, for O2-C3 is 173. kJ/mol.

The interaction of the second lone pair donor orbital, 23, for O4 with the antibonding acceptor orbital, 149, for C3-O5 is 86.3 kJ/mol.

The interaction of lone pair donor orbital, 24, for O5 with the second antibonding acceptor orbital, 148, for C3-O4 is 24.8 kJ/mol.

The interaction of the second lone pair donor orbital, 25, for O5 with the antibonding acceptor orbital, 146, for O2-C3 is 138. kJ/mol.

The interaction of the second lone pair donor orbital, 25, for O5 with the second antibonding acceptor orbital, 148, for C3-O4 is 75.7 kJ/mol.

The interaction of the third lone pair donor orbital, 26, for O5 with the antibonding acceptor orbital, 147, for C3-O4 is 572. kJ/mol.

The interaction of lone pair donor orbital, 27, for O7 with the second antibonding acceptor orbital, 152, for C6-O8 is 24.8 kJ/mol.

The interaction of the second lone pair donor orbital, 28, for O7 with the antibonding acceptor orbital, 145, for O1-C6 is 138. kJ/mol.

The interaction of the second lone pair donor orbital, 28, for O7 with the second antibonding acceptor orbital, 152, for C6-O8 is 75.7 kJ/mol.

The interaction of the third lone pair donor orbital, 29, for O7 with the antibonding acceptor orbital, 151, for C6-O8 is 572. kJ/mol.

The interaction of lone pair donor orbital, 30, for O8 with the antibonding acceptor orbital, 150, for C6-O7 is 23.8 kJ/mol.

The interaction of the second lone pair donor orbital, 31, for O8 with the antibonding acceptor orbital, 145, for O1-C6 is 173. kJ/mol.

The interaction of the second lone pair donor orbital, 31, for O8 with the antibonding acceptor orbital, 150, for C6-O7 is 86.3 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.

35 ----- 11.24

34 ----- 9.323
33 ----- 9.169

32 ----- 6.369

31 -^-v- 3.045
30 -^-v- 3.014
29 -^-v- 2.839

28 -^-v- 2.259
27 -^-v- 2.189
26 -^-v- 2.048

25 -^-v- 1.758

24 -^-v- 0.778

23 -^-v- 0.337

22 -^-v- -1.494
21 -^-v- -1.556
20 -^-v- -1.618

19 -^-v- -2.222

18 -^-v- -2.343

17 -^-v- -2.521

16 -^-v- -3.597

15 -^-v- -5.231

14 -^-v- -13.26

13 -^-v- -14.94
12 -^-v- -15.00

11 -^-v- -15.90

10 -^-v- -17.45

9 -^-v- -18.47

8 -^-v- -261.0 7 -^-v- -261.0

6 -^-v- -496.6 5 -^-v- -496.6

4 -^-v- -496.7 3 -^-v- -496.7

2 -^-v- -499.0 1 -^-v- -499.0

## 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 = -527.7492197954 Hartrees