Angstrom: Difference between revisions

Revision as of 00:27, 10 February 2019

Revision as of 20:35, 18 February 2019

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The [[natural science]]s and [[technology]] often use ångström to express sizes of [[atom]]s, [[molecule]]s, microscopic biological structures, and lengths of [[chemical bond]]s, [[crystallography|arrangement of atoms in crystals]], [[wavelength]]s of [[electromagnetic radiation]], and dimensions of [[integrated circuit]] parts. Atoms of phosphorus, sulfur, and chlorine are about an ångström in covalent radius, while a hydrogen atom is about half an ångström; see [[atomic radius]]. [[Visible light]] has wavelengths in the range of 4000–7000 Å.

The unit is named after the [[Swedish people|Swedish]] physicist [[Anders Jonas Ångström]] (1814–1874). The symbol is always written with the Swedish alphabet letter 'Å'. Though it appears to be of the Latin alphabet 'A' with a [[Ring (diacritic)#Distinct_letter|ring diacritic]], it is ''not''. The unit's name is often written in English with the Latin alphabet 'A',<ref name="webster">''Webster′s Encyclopedic Unabridged Dictionary of the English Language''. Portland House, 1989</ref> but the official definition is the Swedish letter 'Å'.<ref>{{SIBrochure8th |page=127}}</ref><ref>{{cite web

|url = http://physics.nist.gov/Pubs/SP811/appenB8.html

|title = B.8 Factors for Units Listed Alphabetically

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|last1 = Thompson

|first2 = Barry N.

|last2 = Taylor }}</ref> It is not a part of the [[SI]] system of units;, althoughbut it can be considered part of the [[metric system]].

==Use==