Convert X-unit to Angstrom
Convert x-units to angstroms instantly. 1 x-unit = 0.0010021 angstrom — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Angstrom to X-unit converter for the reverse conversion.
Units explained
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Defined by Manne Siegbahn in 1925; superseded by direct SI measurement of X-ray wavelengths after the 1960s; retained in literature for historical comparison.
Angstrom
An angstrom is a unit of length equal to exactly 10⁻¹⁰ meters (0.1 nm). Named after Swedish physicist Anders Jonas Ångström, it is the traditional unit for atomic and molecular dimensions in chemistry and crystallography.
Defined in 1907 as exactly 10⁻¹⁰ m. Although officially deprecated by the BIPM in favor of the nanometer in 1978, the angstrom remains in widespread use in chemistry and crystallography.
Angstroms express bond lengths (typical covalent bond is 1–2 Å), atomic radii, crystal lattice parameters, and X-ray wavelengths. Standard in chemistry textbooks and crystallographic data tables.
Named after Anders Jonas Ångström; defined at 10⁻¹⁰ m in 1907; deprecated as SI by BIPM in 1978 but retained universally in chemistry practice.
X-unit to Angstrom conversion formula
The relationship between x-units and angstroms:
To convert x-units to angstroms, multiply the value in x-units by 0.0010021. To reverse, multiply angstroms by 997.9044007584.
How to use this converter
Type a value into the calculator. The result in angstroms updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Angstrom to X-unit converter for the reverse direction.
Step-by-step: convert x-units to angstroms
- Write down the value in x-units (X).
- Multiply that value by the factor 0.0010021.
- The product is the equivalent value in angstroms (Å).
- To reverse, multiply the angstrom value by 997.9044007584.
Worked examples
Example 1 — Convert 1 X to Å:
1 × 0.0010021 = 0.0010021 Å
Example 2 — Convert 100 X to Å:
100 × 0.0010021 = 0.10021 Å
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 x-units can be re-expressed in angstroms for direct comparison with another instrument's calibration data sheet.
800 X × 0.0010021 = 0.80168 Å
Real-world example — Molecular dimensions
The diameter of small molecular structures (around 2 x-units) is often converted into related sub-micron units when comparing measurements across different microscopy techniques or imaging modalities.
2 X × 0.0010021 = 0.0020042 Å
X-unit to Angstrom conversion table
Standard reference values for converting x-units to angstroms:
| X-unit [X] | Angstrom [Å] |
|---|---|
| 0.01 | 1.0021e-5 |
| 0.1 | 0.00010021 |
| 1 | 0.0010021 |
| 2 | 0.0020042 |
| 3 | 0.0030063 |
| 4 | 0.0040084 |
| 5 | 0.0050105 |
| 10 | 0.010021 |
| 20 | 0.020042 |
| 30 | 0.030063 |
| 40 | 0.040084 |
| 50 | 0.050105 |
| 100 | 0.10021 |
| 500 | 0.50105 |
| 1000 | 1.0021 |
Frequently asked questions
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Sources & references
Conversion factor (1 X = 0.0010021 Å) 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.