Hectometer
A hectometer (hm) is a unit of length in the metric system, equal to 100 meters. It is larger than a meter but smaller than a kilometer. While it is part of the official metric system, the hectometer is rarely used in daily life or science. For example, a running track is 400 meters long, which is 4 hectometers. The symbol for hectometer is "hm". Although not commonly seen, it can be useful for measuring medium-range distances, especially when kilometers feel too large and meters too small.
X-unit
The X-unit (symbol: xu) is a very small unit of length used primarily to measure wavelengths of X-rays and gamma rays. It was introduced in the early 20th century for precision measurements in X-ray crystallography.
1 X-unit ≈ 0.1 picometers (pm) or 10⁻¹³ meters
It allows scientists to express extremely small wavelengths typical of X-rays, which are on the order of atomic spacing
The exact definition has varied historically, but the unit remains useful for comparing wavelengths in X-ray spectroscopy and crystallography
Though largely replaced by the picometer or ångström in modern usage, the X-unit played a crucial role in early developments of atomic-scale measurement.
No conversions available for length.