Definition - What does Angstrom mean?

An ångström is a unit of length equal to one hundred millionth (10-8) of a centimeter, one ten-billionth (10-10) of a meter or 0.1 nm. The unit is widely used in physics, chemistry and biology to express the sizes of extremely small objects.

In corrosion chemistry, an ångström is used to measure corrosion rate, thickness of corrosion products and oxide layers.

An ångström is also known as an ångström unit.

Corrosionpedia explains Angstrom

The ångström is a measure of displacement equal to 0.0000000001 (10-10) meter, named after the Swedish physicist Anders Jonas Ångström (1814-1874). Its symbol is Å, a letter in the Scandinavian alphabets. The symbol is always written with a ring diacritic. Although the unit's name is often written in English without the diacritics,the official definitions contain diacritics.

The ångström is often used in the natural sciences and technology to express:

  • Sizes of atoms, molecules and microscopic biological structures
  • Lengths of chemical bonds
  • Arrangement of atoms in crystals
  • Wavelengths of electromagnetic radiation
  • Dimensions of integrated circuit parts

The angstrom and multiples of it are also used to measure quantities such as molecular diameters and the thickness of films on liquids or oxide layers on metal surfaces. One ångström is equal to 10 millimicrons or 10-4 microns. It is sometimes used to express wavelengths of visible light, ultraviolet (UV) light, X rays and gamma rays.

The ångström is not commonly used anymore. It has been largely superseded by the nanometer, which is 10 times larger.

Although internationally recognized, the ångström is not formally a part of the International System of Units (SI). The closest SI unit is the nanometer (10-9 m). Its use is officially discouraged by the International Committee for Weights and Measures and is not included in the European Union's catalog of units of measure that may be used within its Internal Market.

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