Title: dipolar compounds
Long Title: IUPAC Gold Book - dipolar compounds
DOI: 10.1351/goldbook.D01753
Status: current

Definition
Electrically neutral molecules carrying a positive and a negative charge in one of their major canonical descriptions. In most dipolar compounds the charges are delocalized; however the term is also applied to species where this is not the case. 1,2-Dipolar compounds have the opposite charges on adjacent atoms. The term 1,3-dipolar compounds is used for those in which a significant canonical resonance form can be represented by a separation of charge over three atoms (in connection with 1,3-dipolar cycloadditions). Subclasses of 1,3-dipolar compounds include:
Allyl type $\ce{X=Y^{+}-Z^{−}}$$\ce{}$$\ce{X^{−}-Y^{+}=Z}$$\ce{}$$\ce{X^{+}-Y-Z^{−}}$$\ce{}$$\ce{X^{−}=Y-Z^{+}}$ $(\ce{X, Z = C, N, or O; Y = N or O})$See: azo imides, azomethine imides, azomethine ylides, azoxy compounds, carbonyl imides, carbonyl oxides, carbonyl ylides, nitro compounds, nitrones
Propargyl type $\ce{X#N^{+}-Z^{−}}$$\ce{}$$\ce{X^{−}=N^{+}=Z}$$\ce{}$$\ce{X^{−}=N-Z^{+}}$$\ce{}$$\ce{X-N=Z}$ $(\ce{X = C or O, Z = C, N, or O})$See: azides, diazo compounds, nitrile imides, nitrile oxides, nitrile ylides, nitrilium betaines
Carbene type $\ce{X{:}-C=Z}$$\ce{}$$\ce{X^{+}=C-Z^{−}}$ $(\ce{X = C or N; Z = C, N, or O})$See: acyl carbenes, betaines, imidoyl carbenes, vinyl carbenes


Related Terms
- acyl carbenes: https://goldbook.iupac.org//terms/view/A00121
- azides: https://goldbook.iupac.org//terms/view/A00555
- azo imides: https://goldbook.iupac.org//terms/view/A00561
- azomethine imides: https://goldbook.iupac.org//terms/view/A00562
- azomethine ylides: https://goldbook.iupac.org//terms/view/A00565
- azoxy compounds: https://goldbook.iupac.org//terms/view/A00567
- betaines: https://goldbook.iupac.org//terms/view/B00637
- carbonyl imides: https://goldbook.iupac.org//terms/view/C00845
- carbonyl oxides: https://goldbook.iupac.org//terms/view/C00847
- carbonyl ylides: https://goldbook.iupac.org//terms/view/C00848
- diazo compounds: https://goldbook.iupac.org//terms/view/D01691
- imidoyl carbenes: https://goldbook.iupac.org//terms/view/I02953
- nitrile imides: https://goldbook.iupac.org//terms/view/N04148
- nitrile oxides: https://goldbook.iupac.org//terms/view/N04150
- nitrile ylides: https://goldbook.iupac.org//terms/view/N04153
- nitrilium betaines: https://goldbook.iupac.org//terms/view/N04155
- nitro compounds: https://goldbook.iupac.org//terms/view/N04158
- nitrones: https://goldbook.iupac.org//terms/view/N04164
- resonance: https://goldbook.iupac.org//terms/view/R05326
- vinyl carbenes: https://goldbook.iupac.org//terms/view/V06620

Source
- PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1333 (https://doi.org/10.1351/pac199567081307)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/D01753/html
- json: https://goldbook.iupac.org/terms/view/D01753/json
- xml: https://goldbook.iupac.org/terms/view/D01753/xml

Citation: Citation: 'dipolar compounds' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.D01753
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Accessed: 2026-01-31T06:29:43+00:00