# Definition:Angstrom (Unit)

## Angstrom

The angstrom is a metric unit of length.

 $\ds$  $\ds 1$ angstrom $\ds$ $=$ $\ds 10^{-4}$ micrometres $\ds$ $=$ $\ds 10^{-7}$ millimetres $\ds$ $=$ $\ds 10^{-10}$ metres

### Symbol

$\mathring {\mathrm A}$

The symbol for the angstrom is $\mathring {\mathrm A}$.

Its $\LaTeX$ code is \mathring {\mathrm A} .

## Source of Name

This entry was named for Anders Jonas Ångström.

## Historical Note

The angstrom was formally used for measurements of wavelengths and intramolecular distances, but has been superseded by the nanometre ($10^{-9} \, \mathrm m$)

## Linguistic Note

The word angstrom is derived from a Swedish name, and properly has diacritics: ångström.

However, this "correct" presentation is tedious to implement and a nuisance to maintain, so $\mathsf{Pr} \infty \mathsf{fWiki}$ prefers the simple version angstrom.

Its symbol, however, does need the small circle above the A in order to be accurate and unambiguous.

This, unfortunately, is not straightforward to render in $\LaTeX$ without including further expansion sets.

Hence the $\LaTeX$ form as $\mathring {\mathrm A}$ (not a strictly accurate rendition) is how it is presented on $\mathsf{Pr} \infty \mathsf{fWiki}$.