Instant · Precise · Universal
32 units available
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To convert to meters: multiply by 2.8179403262 × 10⁻¹⁵.
re = e²/(4πε₀mec²) ≈ 2.8179 × 10⁻¹⁵ m, where e is electron charge and me is electron mass.
For example, 1 Electron Radius (Classical) (re) = 0.002817940326 Picometer (pm).
| Electron Radius (Classical) (re) | Picometer (pm) |
|---|---|
| 0.1 | 0.0002817940326 |
| 0.5 | 0.001408970163 |
| 1 | 0.002817940326 |
| 2 | 0.005635880652 |
| 5 | 0.01408970163 |
| 10 | 0.02817940326 |
| 25 | 0.07044850815 |
| 50 | 0.1408970163 |
| 100 | 0.2817940326 |
| 500 | 1.408970163 |
| 1000 | 2.817940326 |
The classical electron radius is a theoretical length scale derived from the electron's charge and mass, approximately 2.818 × 10⁻¹⁵ meters.
re = e²/(4πε₀mec²) ≈ 2.8179 × 10⁻¹⁵ m, where e is electron charge and me is electron mass.
To convert to meters: multiply by 2.8179403262 × 10⁻¹⁵.
Used in calculating X-ray and gamma-ray scattering probabilities off electrons (Thomson and Compton scattering).
Despite its name, the electron is a point particle in quantum theory — the 'classical radius' is a theoretical construct, not the electron's actual size.
Assuming this is the actual physical size of the electron — quantum mechanics shows the electron has no measurable size.
Think of it as the scale at which classical electromagnetic self-energy equals the electron's mass-energy.
The picometer is a unit of length equal to 10⁻¹² meters, or one trillionth of a meter.
1 pm = 10⁻¹² m = 0.01 Å = 1,000 fm. One nanometer equals 1,000 picometers.
To convert pm to meters: multiply by 10⁻¹². To convert pm to angstroms: divide by 100.
Expressing covalent bond lengths (e.g., C–C bond ≈ 154 pm), atomic radii, and crystal lattice spacings.
The hydrogen atom has a radius of about 53 pm (the Bohr radius), while a carbon-carbon single bond is about 154 pm long.
Mixing up picometers and nanometers — remember 1 nm = 1,000 pm. Some sources still use the deprecated angstrom.
Think of pm as the natural unit for atoms: most atomic radii fall between 30 pm and 300 pm.



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