A Lewis electron dot diagram (or electron dot diagram or a Lewis diagram or a Lewis structure) is a representation of the valence electrons of an atom that uses dots around the symbol of the element. The number of dots equals the number of valence electrons in the atom. Apr 01, 2013 Lewis structures are a way to write chemical compounds where all the atoms and electrons are shown. Sometimes, people have a lot of trouble learning how to do this. However, using the methods on this page, you should have very little trouble.

Molecular Structure Calculations

Colby Chemistry, Paul J. Schupf Computational Chemistry Lab

The simple theories of bonding that we learn in General Chemistry are powerfuland useful. These theories, which include Lewis structures, VSEPR, andhybridization, are simple models that help predict chemicalproperties. However, Lewis dot structures and hybridization are approximationsthat may or may not match reality. We should verify the usefulness of oursimple predictions with molecular orbital theory. If thetheoretical calculations are done carefully, we can learn a lot about chemical structure by comparing our Lewis structures and hybridizationarguments with the molecular orbitals.

The calculations in this database includebond lengths, angles, atomic charges, the dipole moment,bond orders, and molecular orbital energies. The best Lewis structure thatfits the molecular orbitals is also calculated, so you can directlycompare with your predictions. This best Lewis structure is presented withformal electron pair localized bonds and the hybridization of the atomicorbitals used to form these localized bonds. The Chime plugin is neededto see the 3-D structure of the molecules in these pages. See thelink at the bottom of the page for the Chime plugin.

Molecular orbital theory is based on approximations also. These calculationsare done with some of the best available calculation methods (DFT forgeometry and molecular orbital energies and ab initio for properties).We use Alain St-Amant's DeFT program (University of Ottawa).

The Molecular Structure Input Form, see below, will allow you to do calculationsfor molecules not in the database.These calculations take time; 1-2 hours in some cases.

You can use the Formula Search page or browse the links below. As of 07/12/05 there are 1056structures in the database.
A Best Lewis Structure and Donor Acceptor Interactions Tutorialis available to help you interpret those output sections. These Lewisstructure calculations are done using NBO Analysis.
Answer some Study Questions to help your understanding of some interesting chemistry.

Example Molecular Orbital Results

LiHLiFLiClLiOHLiCNLiBrC₂N₂NOO₂COF₂

Many More Diatomic molecules and ions

H₃⁺Li₂OBeH₂BeCl₂diboraneBH₃BH₂CNBH₂SH
BF₃BF₃2-BF₄⁺BF₂O^-BCl₃BH₃NH₃BH₃COBH₃PH₃BO₂NO
C₃C₅H₂OH₃O⁺H₄O⁺O₃O₄CO₂OCScyclic CO₂CO₂^-HCO⁺HOC⁺
N₃ radicalN₃ quartetHN₃N₃^-NCOHNCNHCNNO
NO₂NO₂⁺NO₂^-HOONNOO^-NO₂^- triplet NO₂²⁺NO₃^-NO₃^-triplet NO₂O^-
N₂Ocyclic N₂Ocyclic N₂O₂N₂O₄NO₂NO
ONOOHN₂H₂N₂H₂ tripletH₂NNH₂NN tripletNH₂FNHF₂NF₃NF₄^-N₂F₂N₂F₄BNHF
HNCl⁺NH₂ClN₃ClNCl₂NCl₃NOClONClNClOClNO₂ClNOOt-ClONOOCl₂
OF₂FOO•FOOFFNO₂FOONF₃^-Cl₃^-Cl₃FClF₂⁺
AlH₃AlF₃AlCl₃Al₂Cl₆
SiH₄SiH₃SiH₃SiO₂
P₂PCl₃SO₂SO₃SO₃^-SOCl₂SO₂Cl₂ClO₂ClOOClO₂⁺ClO₂^-ClOO^-
FClOFClO₂K₂O

Many More Binary Hydrides and their Anions, Cations, and Radicals
Many More Triatomic molecules and their Anions, Cations, and Radicals
Many More Period 3 Compounds, Al, Si, P, S, and Cl
Many More Period 4 Compounds, Ga, Ge, As, Se, and Br

Acids

Onium Ions:NH₄⁺NH₃F⁺NH₃Cl⁺ Calculator

H₃O⁺H₃O₂⁺H₂F⁺PH₄⁺H₃S⁺H₂Cl⁺H₂CN⁺
Hydrides:HFHClHCNHCN tripletHNCHNCOHOCNHONCHCNOHNCSHSCNHN₃
H₂N₂H₂N=NN₂H₄H₂O₂P₂H₄H₂SH₂S₂
Oxyacids:H₂CO₃HONHNOHNO₂HNO₃H₂O₂HOFHOCl
HClO₃HClO₄H₃PO₂H₃PO₃H₃PO₄HSOHH₂SO₃H₂SO₄

Anions

Hydride Conjugates:F^-Cl^-OH^-CN^-NCO^-CNO^-NCS^-CNS^-NSC^-N₃^-HN₂^-N₂H₃^-HOO^-
P₂H₃^-HS^-
Oxyanions:HCO₃^-CO₃^2-CO₃OH^-CO₃O^2-NO^-NO₂^-NO₃^-HO₂^-O₂^2-OF^-OCl^-ClO₂^-
ClO₃^-ClO₄^-H₂PO₂^-H₂PO₃^-H₂PO₄^-HPO₄^2-PO₄^3-HOS^-HSO^-
HSO₃^-SO₃^2-HSO₄^-SO₄^2-S₂O₃^2-

Many MoreHydroxyl Compounds, Donor-Acceptor Oxides, Oxyacids, and Anions
Many MoreFormally Double Bonded Hydroxyl Compounds, Donor-Acceptor Oxides, and Oxyacids (e.g.Carbonic and Nitric acid)

Organics

ethaneethyleneacetyleneH₂C=C, vinylidene
methanolformaldehydeformic acidmethylamineCF₃Cl

Many More Carbon Compounds, Organics, and Organic Reagents
Many MoreOrganic Radical Cations, Neutral Radicals, Cations, and Anions

Oxides

NH₃->OCH₃NH₂->OCH₂NH->OCH₃OH->OCH₂O->OCH₂O->O tripletH₂N₂->O
PH₃->OCH₃PH₂->OH₂S->OCH₃SH->OCH₃F->OCH₃OFCH₃Cl->OH₂S->O₂

Reactive Intermediates

OH radicalHOO radicalH₂O₂⁺ radicalHCO₃ radicalCO₃^- radical CO₃OH^-CO₃O^2-peroxodicarbonate dianion, O₂COOCO₂^2-
methylene singlet (CH₂)methylene triplet (CH₂)methyl radical (CH₃)CH₃⁺
ethyl radical (CH₃CH₂)CH₃CH₂⁺ethylene tripletcyclopropane radicalHCC•HCC^-
CH₃NH^-CH₃OH⁺CH₃OH₂

Lewis Dot Structure Calculator Wolfram Chart

⁺CH₃O^-CH₃O radicalCH₂OH⁺CH₃CO⁺CH₂CHO^-