Convert Chain (US Survey) (ch (US)) to Picometer (pm) instantly.
About these units
Chain (US Survey) (ch (US))
The US Survey Chain is defined as 66 US Survey Feet (~20.1168 meters), aligning with the historic Gunter's chain but adapted to the US survey foot. It is used primarily in cadastral surveys, property delineation, and historical land records. Surveyors employ the chain for practical measurements of fields, lots, and infrastructure layouts. The unit's subdivision into 100 links simplifies area calculation, as 10 square chains equal one acre, maintaining continuity with older surveying systems. Even today, engineers and surveyors working with legacy data encounter the US survey chain in historical deeds, maps, and legal descriptions. Its precision ensures consistency when reconciling pre-modern measurements with modern coordinates.
Picometer (pm)
At 10⁻¹² meters, the picometer occupies a scale close to the dimensions of atoms but slightly finer than typical atomic radii. Chemists use picometers to express covalent bond lengths, ionic radii, and atomic radii. For example, the radius of a hydrogen atom is about 53 pm. The unit also appears frequently in crystallography, where X-ray diffraction reveals lattice spacing on the order of a few hundred picometers. The picometer provides a numeric convenience: atomic structures are neither too large nor too small to measure accurately in this unit. In physics, picometer-scale distances become relevant when examining the interactions of electrons in tightly bound orbitals or in high-resolution measurements of electric dipole moments. It is a unit that bridges atomic size with the precision of modern measurement tools.