## B(OH)2O- ion*

 O3 / \ O1 = B2 H4 \ O5 / H6
The ion charge is -1.

## Atomic Charges and Dipole Moment

O1 charge=-0.944
B2 charge= 0.872
O3 charge=-0.825
H4 charge= 0.401
O5 charge=-0.876
H6 charge= 0.372
with a dipole moment of 3.82140 Debye

## Bond Lengths:

between O1 and B2: distance=1.307 ang___ between O1 and O3: distance=2.477 ang___
between O1 and O5: distance=2.474 ang___ between B2 and O3: distance=1.454 ang___
between B2 and O5: distance=1.484 ang___ between O3 and H4: distance=0.976 ang___
between O3 and O5: distance=2.375 ang___ between O5 and H6: distance=0.974 ang___

## Bond Angles:

for O3-B2-O1: angle=127.4 deg___ for H4-O3-B2: angle=106.0 deg___
for O5-B2-O1: angle=124.7 deg___ for H6-O5-B2: angle=102.5 deg___

## Bond Orders (Mulliken):

between O1 and B2: order=1.756___ between O1 and O3: order=-0.140___
between O1 and O5: order=-0.175___ between B2 and O3: order=0.952___
between B2 and O5: order=0.901___ between O3 and H4: order=0.885___
between O3 and O5: order=-0.146___ between O5 and H6: order=0.875___

## 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-B2 with 1.9193 electrons
__has 87.04% O 1 character in a sp2.19 hybrid
__has 12.96% B 2 character in a sp2.43 d1.01 hybrid

2. A bonding orbital for O1-B2 with 1.9984 electrons
__has 87.08% O 1 character in a p-pi orbital ( 99.90% p 0.10% d)
__has 12.92% B 2 character in a p-pi orbital ( 98.79% p 1.21% d)

3. A bonding orbital for O1-B2 with 1.9233 electrons
__has 90.93% O 1 character in a s0.68 p3 hybrid
__has 9.07% B 2 character in a s0.91 p3 d1.54 hybrid

4. A bonding orbital for B2-O3 with 1.9466 electrons
__has 16.34% B 2 character in a sp1.90 d0.45 hybrid
__has 83.66% O 3 character in a sp1.47 hybrid

5. A bonding orbital for B2-O5 with 1.9458 electrons
__has 15.66% B 2 character in a sp1.71 d0.45 hybrid
__has 84.34% O 5 character in a sp1.61 hybrid

6. A bonding orbital for O3-H4 with 1.9875 electrons
__has 72.58% O 3 character in a s0.72 p3 hybrid
__has 27.42% H 4 character in a s orbital

7. A bonding orbital for O5-H6 with 1.9889 electrons
__has 73.34% O 5 character in a s0.75 p3 hybrid
__has 26.66% H 6 character in a s orbital

12. A lone pair orbital for O1 with 1.9760 electrons
__made from a sp0.99 hybrid

13. A lone pair orbital for O3 with 1.9821 electrons
__made from a sp1.48 hybrid

14. A lone pair orbital for O3 with 1.9297 electrons
__made from a p-pi orbital ( 99.95% p)

15. A lone pair orbital for O5 with 1.9830 electrons
__made from a sp1.39 hybrid

16. A lone pair orbital for O5 with 1.9379 electrons
__made from a p-pi orbital ( 99.96% p)

103. A antibonding orbital for O1-B2 with 0.1230 electrons
__has 12.92% O 1 character in a p-pi orbital ( 99.90% p 0.10% d)
__has 87.08% B 2 character in a p-pi orbital ( 98.79% p 1.21% d)

104. A antibonding orbital for O1-B2 with 0.1159 electrons
__has 9.07% O 1 character in a s0.68 p3 hybrid
__has 90.93% B 2 character in a s0.91 p3 d1.54 hybrid

-With core pairs on: O 1 B 2 O 3 O 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 bonding donor orbital, 1, for O1-B2 with the third antibonding acceptor orbital, 104, for O1-B2 is 414. kJ/mol.

The interaction of bonding donor orbital, 1, for O1-B2 with the antibonding acceptor orbital, 105, for B2-O3 is 138. kJ/mol.

The interaction of bonding donor orbital, 1, for O1-B2 with the antibonding acceptor orbital, 106, for B2-O5 is 103. kJ/mol.

The interaction of the third bonding donor orbital, 3, for O1-B2 with the antibonding acceptor orbital, 102, for O1-B2 is 305. kJ/mol.

The interaction of the third bonding donor orbital, 3, for O1-B2 with the antibonding acceptor orbital, 105, for B2-O3 is 97.6 kJ/mol.

The interaction of the third bonding donor orbital, 3, for O1-B2 with the antibonding acceptor orbital, 106, for B2-O5 is 133. kJ/mol.

The interaction of bonding donor orbital, 4, for B2-O3 with the antibonding acceptor orbital, 102, for O1-B2 is 171. kJ/mol.

The interaction of bonding donor orbital, 4, for B2-O3 with the third antibonding acceptor orbital, 104, for O1-B2 is 213. kJ/mol.

The interaction of bonding donor orbital, 4, for B2-O3 with the antibonding acceptor orbital, 106, for B2-O5 is 100. kJ/mol.

The interaction of bonding donor orbital, 5, for B2-O5 with the antibonding acceptor orbital, 102, for O1-B2 is 146. kJ/mol.

The interaction of bonding donor orbital, 5, for B2-O5 with the third antibonding acceptor orbital, 104, for O1-B2 is 242. kJ/mol.

The interaction of bonding donor orbital, 5, for B2-O5 with the antibonding acceptor orbital, 105, for B2-O3 is 102. kJ/mol.

The interaction of bonding donor orbital, 6, for O3-H4 with the antibonding acceptor orbital, 102, for O1-B2 is 36.6 kJ/mol.

The interaction of lone pair donor orbital, 13, for O3 with the third antibonding acceptor orbital, 104, for O1-B2 is 31.5 kJ/mol.

The interaction of the second lone pair donor orbital, 14, for O3 with the second antibonding acceptor orbital, 103, for O1-B2 is 143. kJ/mol.

The interaction of lone pair donor orbital, 15, for O5 with the third antibonding acceptor orbital, 104, for O1-B2 is 38.1 kJ/mol.

The interaction of the second lone pair donor orbital, 16, for O5 with the second antibonding acceptor orbital, 103, for O1-B2 is 128. 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.

20 ----- 7.422

19 ----- 6.594
18 ----- 6.090
17 ----- 5.492

16 -^-v- 0.424

15 -^-v- -0.168

14 -^-v- -1.632

13 -^-v- -1.972

12 -^-v- -2.960

11 -^-v- -3.328

10 -^-v- -4.057

9 -^-v- -6.778

8 -^-v- -7.302

7 -^-v- -15.74

6 -^-v- -18.52

5 -^-v- -19.47

4 -^-v- -169.5

3 -^-v- -498.1

2 -^-v- -500.7
1 -^-v- -500.7

## 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 = -252.0085452564 Hartrees

* Note that this is not the anion that is responsible for the acidic behavior of boric acid. The acidity of boric acid is the result of the reaction:
B(OH)3 + OH- -> B(OH)4-