ångström
Encyclopedia : N : NG : NGS : ångström
An angstrom, angström, or ångström (symbol Å) is a unit of length. It is not an SI unit. It is accepted (although discouraged) for use with the SI. It is sometimes used expressing the size of atoms, and lengths of chemical bonds and visible-light spectra.
Definition
For an example of lengths in this unit, the average diameter of an atom, calculated from its empirical radius, ranges from approximately 0.5 Å for hydrogen (the smallest element) to 3.8 Å for uranium (the largest naturally occurring elements on Earth).Origin
The ångström is named after the Swedish physicist Anders Jonas Ångström (1814–1874), one of the founders of spectroscopy. Besides astrophysics, Ångström was also a student of heat transfer, terrestrial magnetism, and the aurora borealis, which was so prominent for him in his northern skies. He created a spectrum chart of solar radiation that expresses the length of electromagnetic radiation in the electromagnetic spectrum on the order of multiples of one ten-millionth of a millimeter, or 1×10-10 meters. This unit of length became known as the ångström, Å.
Representation in Unicode
Unicode includes the "angstrom sign" at U+212B (which looks like Å in a web browser). However, the "angstrom sign" is canonically decomposed into U+00C5 (Å), thereby seen as a (preexisting) encoding mistake, and it is better to use U+00C5 (Å) directly.
See also
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.