201Hg

201Hg is a stable isotope of the element mercury (Hg) with a mass number of 201. It contains 80 protons and 121 neutrons and is one of the seven stable mercury isotopes (196, 198, 199, 200, 201, 202, and 204).

In natural mercury, 201Hg accounts for about 13% of all mercury atoms, though the exact fraction varies slightly between samples. Because it is stable, 201Hg does not undergo radioactive decay and has no radioactive half-life.

Occurrence and measurement: 201Hg occurs naturally as part of the isotopic mix in mercury-bearing rocks and in elemental mercury. It can be measured and quantified using mass spectrometry, and its abundance contributes to the standard atomic weight of natural mercury, which is about 200.59.

Applications and significance: The isotopic composition of mercury, including 201Hg, is used in geochemical and environmental studies to investigate mercury sources and cycling. Isotope-ratio measurements help in tracing contamination pathways, studying mercury biogeochemical processes, and calibrating analytical methods for mercury quantification.

Safety: Mercury and its compounds are highly toxic; handling of mercury isotopes requires appropriate safety precautions and containment to prevent exposure.