Convert Bohr Radius to X-unit
Convert bohr radii to x-units instantly. 1 bohr radius = 528.0682675412 x-unit — use the live calculator, the exact formula, a conversion table and worked examples. Also check the X-unit to Bohr Radius converter for the reverse conversion.
Units explained
Bohr Radius
The Bohr radius is approximately 5.292×10⁻¹¹ meters — the most probable distance between the proton and electron in a hydrogen atom in its ground state.
Defined by Niels Bohr in his 1913 model of the hydrogen atom. The current CODATA 2018 value of 5.29177210903×10⁻¹¹ m is derived from the elementary charge, electron mass, and Planck's constant.
The Bohr radius is used throughout atomic physics, quantum chemistry, and computational chemistry as the natural length scale for electronic-structure calculations. The atomic unit (a.u.) of length equals the Bohr radius.
Defined by Bohr in 1913; current value via CODATA 2018.
X-unit
The X-unit (or siegbahn) is a historical X-ray crystallography unit of approximately 1.0021×10⁻¹³ meters. It was used before X-ray wavelengths could be measured directly in meters.
Introduced by Manne Siegbahn in 1925 as a self-consistent unit for X-ray crystallography. The 'X-unit' was defined to make the X-ray wavelength of the molybdenum K-alpha line a round number.
X-units appear in X-ray crystallography literature from 1925 through the 1960s. Modern crystallography uses meters or angstroms; X-units are mostly of historical interest now.
Defined by Manne Siegbahn in 1925; superseded by direct SI measurement of X-ray wavelengths after the 1960s; retained in literature for historical comparison.
Bohr Radius to X-unit conversion formula
The relationship between bohr radii and x-units:
To convert bohr radii to x-units, multiply the value in bohr radii by 528.0682675412. To reverse, multiply x-units by 0.0018936945.
How to use this converter
Type a value into the calculator. The result in x-units updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the X-unit to Bohr Radius converter for the reverse direction.
Step-by-step: convert bohr radii to x-units
- Write down the value in bohr radii (a₀).
- Multiply that value by the factor 528.0682675412.
- The product is the equivalent value in x-units (X).
- To reverse, multiply the x-unit value by 0.0018936945.
Worked examples
Example 1 — Convert 1 a₀ to X:
1 × 528.0682675412 = 528.0682675412 X
Example 2 — Convert 100 a₀ to X:
100 × 528.0682675412 = 52806.8267541164 X
Real-world example — Wavelengths across the spectrum
Optical and atomic-scale phenomena are routinely cross-converted between sub-micron units. A photon of wavelength 800 bohr radii can be re-expressed in x-units for direct comparison with another instrument's calibration data sheet.
800 a₀ × 528.0682675412 = 422454.6140329308 X
Real-world example — Molecular dimensions
The diameter of small molecular structures (around 2 bohr radii) is often converted into related sub-micron units when comparing measurements across different microscopy techniques or imaging modalities.
2 a₀ × 528.0682675412 = 1056.1365350823 X
Bohr Radius to X-unit conversion table
Standard reference values for converting bohr radii to x-units:
| Bohr Radius [a₀] | X-unit [X] |
|---|---|
| 0.01 | 5.2806826754 |
| 0.1 | 52.8068267541 |
| 1 | 528.0682675412 |
| 2 | 1056.1365350823 |
| 3 | 1584.2048026235 |
| 4 | 2112.2730701647 |
| 5 | 2640.3413377058 |
| 10 | 5280.6826754116 |
| 20 | 10561.3653508233 |
| 30 | 15842.0480262349 |
| 40 | 21122.7307016465 |
| 50 | 26403.4133770582 |
| 100 | 52806.8267541164 |
| 500 | 264034.1337705818 |
| 1000 | 528068.2675411636 |
Frequently asked questions
How many x-units is 1 bohr radius?
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Metric / SI (4 units)
Imperial / US Customary (4 units)
Sources & references
Conversion factor (1 a₀ = 528.0682675412 X) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.