Ångstroms

The ångstrom is a unit of length commonly used in atomic and molecular physics, optics, and spectroscopy. It is equal to one ten-billionth of a meter, or 10⁻¹⁰ meters. The symbol for the ångstrom is Å. This unit is named after the Swedish physicist Anders Jonas Ångström, a pioneer in the study of spectroscopy.

While not an official SI (International System of Units) unit, the ångstrom is still widely used due to its convenient size for measuring atomic and molecular dimensions. For example, the diameter of a typical atom is on the order of 1 ångstrom, and the length of a chemical bond is also in the range of a few ångstroms. X-ray wavelengths are also frequently expressed in ångstroms.

The ångstrom is equivalent to 0.1 nanometers or 100 picometers. In the context of the SI system, the ångstrom is often replaced by the nanometer (nm) or picometer (pm), where 1 nm = 10 Å and 1 pm = 0.01 Å. Despite the availability of SI units, the ångstrom persists in many scientific fields due to historical convention and its intuitive representation of atomic-scale phenomena.