Atomic length converter
Convert bond lengths, atomic radii and crystal spacings between ångströms, picometers, nanometers and Bohr radii.
That's about the same as a C–C single bond.
What it means
How small is that?
Atoms have no sharp edge; radii depend on how they are measured (covalent, van der Waals, ionic).
Every unit
That length in every unit
Learn
Three things worth knowing
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1 Å = 100 pm
Multiply ångströms by 100 for picometers, divide by 10 for nanometers.
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Ångström’s spectra
Swedish physicist Anders Ångström measured the Sun’s spectral lines in units of 10⁻¹⁰ m in 1868; the unit took his name.
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Å is not SI
The ångström is not an SI unit; journals increasingly ask for pm or nm. 3.5 Å is 0.35 nm.
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Background
About atomic lengths
Atoms are about one ångström (10⁻¹⁰ m) across, which is why chemists and crystallographers use it: a carbon–carbon single bond is 1.54 Å, or 154 picometers.
Theoretical physicists use the Bohr radius, 0.529 Å, the most likely distance of a hydrogen atom’s electron. Nuclei are 100,000 times smaller, measured in femtometers.