A capital A with a small ring above it, marking a length of 10⁻¹⁰ metres.
Also known as: Angstrom
Å is the ångström, a non-SI unit of length equal to one ten-billionth of a metre. It survives in crystallography and atomic physics because atomic radii and bond lengths fall naturally in single digits when expressed in it.
Marks a length of 10⁻¹⁰ metres, equal to 0.1 nanometres.
Contexts: Mathematics
Is not an SI unit and is not on the SI's list of units accepted for use with it, but persists in crystallography and atomic physics because interatomic distances come out as convenient single-digit numbers.
Contexts: Mathematics
Is encoded twice: U+212B ANGSTROM SIGN exists for compatibility, but U+00C5 LATIN CAPITAL LETTER A WITH RING ABOVE is the character normally recommended, since the two are canonically equivalent.
Contexts: Software
A capital Latin A — two diagonals meeting at a point with a horizontal crossbar — carrying a small open ring centred directly above its apex.