What is the Bohr radius?
The Bohr radius is a_0 = 5.29177210903e-11 m (uncertainty ±8.0e-21), about 0.529 angstroms. It is the most probable electron-proton distance in hydrogen's ground state.
Open the interactive PhysRef tool →Key facts
| Value | 5.29177210903e-11 m |
|---|---|
| Symbol | a_0 |
| In angstroms | ≈ 0.529 Å |
| Uncertainty | ±8.0e-21 m |
| Source | CODATA 2018 |
Frequently asked questions
What is the value of the Bohr radius?
a_0 = 5.29177210903e-11 m, roughly 0.529 angstroms or 52.9 picometres.
What does the Bohr radius represent?
It is the radius of the smallest electron orbit in the Bohr model of hydrogen and sets the atomic length scale.
Is the Bohr radius exact?
No. It has a tiny measured uncertainty of ±8.0e-21 m.
Related pages
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