## HNCO, Cyanic acid

 H3 \ N1 = C2 = O4
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

N1 charge=-0.623
C2 charge= 0.589
H3 charge= 0.379
O4 charge=-0.345
with a dipole moment of 2.35626 Debye

## Bond Lengths:

between N1 and C2: distance=1.221 ang___ between N1 and H3: distance=1.014 ang___
between N1 and O4: distance=2.401 ang___ between C2 and O4: distance=1.184 ang___

## Bond Angles:

for H3-N1-C2: angle=128.8 deg___ for O4-C2-N1: angle=172.8 deg___

## Bond Orders (Mulliken):

between N1 and C2: order=1.792___ between N1 and H3: order=0.833___
between N1 and O4: order=0.139___ between C2 and O4: order=1.801___

## 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 N1-C2 with 1.9967 electrons
__has 58.08% N 1 character in a sp1.60 hybrid
__has 41.92% C 2 character in a sp0.86 hybrid

2. A bonding orbital for N1-C2 with 1.9965 electrons
__has 73.84% N 1 character in a p-pi orbital ( 99.79% p 0.21% d)
__has 26.16% C 2 character in a p-pi orbital ( 99.52% p 0.48% d)

3. A bonding orbital for N1-H3 with 1.9415 electrons
__has 71.59% N 1 character in a sp2.72 hybrid
__has 28.41% H 3 character in a s orbital

4. A bonding orbital for C2-O4 with 1.9966 electrons
__has 35.84% C 2 character in a sp1.27 hybrid
__has 64.16% O 4 character in a sp1.81 hybrid

5. A bonding orbital for C2-O4 with 1.9931 electrons
__has 22.20% C 2 character in a s0.07 p3 hybrid
__has 77.80% O 4 character in a s0.06 p3 hybrid

9. A lone pair orbital for N1 with 1.7487 electrons

10. A lone pair orbital for O4 with 1.9722 electrons

11. A lone pair orbital for O4 with 1.7128 electrons
__made from a p-pi orbital ( 99.81% p 0.19% d)

75. A antibonding orbital for N1-C2 with 0.2756 electrons
__has 26.16% N 1 character in a p-pi orbital ( 99.79% p 0.21% d)
__has 73.84% C 2 character in a p-pi orbital ( 99.52% p 0.48% d)

78. A antibonding orbital for C2-O4 with 0.2537 electrons
__has 77.80% C 2 character in a s0.07 p3 hybrid
__has 22.20% O 4 character in a s0.06 p3 hybrid

-With core pairs on: N 1 C 2 O 4 -

#### 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, 3, for N1-H3 with the antibonding acceptor orbital, 77, for C2-O4 is 20.4 kJ/mol.

The interaction of bonding donor orbital, 3, for N1-H3 with the second antibonding acceptor orbital, 78, for C2-O4 is 80.9 kJ/mol.

The interaction of lone pair donor orbital, 9, for N1 with the antibonding acceptor orbital, 77, for C2-O4 is 75.7 kJ/mol.

The interaction of lone pair donor orbital, 9, for N1 with the second antibonding acceptor orbital, 78, for C2-O4 is 264. kJ/mol.

The interaction of lone pair donor orbital, 10, for O4 with the antibonding acceptor orbital, 74, for N1-C2 is 81.0 kJ/mol.

The interaction of the second lone pair donor orbital, 11, for O4 with the second antibonding acceptor orbital, 75, for N1-C2 is 666. kJ/mol.

The interaction of the second antibonding donor orbital, 78, for C2-O4 with the antibonding acceptor orbital, 76, for N1-H3 is 28.4 kJ/mol.

The interaction of the second antibonding donor orbital, 78, for C2-O4 with the antibonding acceptor orbital, 77, for C2-O4 is 33.0 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.

15 ----- 3.019

14 ----- 0.688

13 ----- -0.044

12 ----- -1.286

11 -^-v- -7.619

10 -^-v- -8.151

9 -^-v- -11.46
8 -^-v- -11.52

7 -^-v- -12.47

6 -^-v- -15.35

5 -^-v- -23.61

4 -^-v- -27.75

3 -^-v- -270.2

2 -^-v- -378.2

1 -^-v- -508.0

## 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 = -168.7528220536 Hartrees