45Sc

45Sc, or scandium-45, is the only stable isotope of scandium (atomic number 21). It has mass number 45 and is 100% naturally occurring, so natural scandium is monoisotopic.

Nuclear properties: The nucleus of 45Sc has a spin of I = 7/2 and a nonzero electric quadrupole moment, indicating a non-spherical charge distribution. As a stable isotope, it does not undergo radioactive decay and remains effectively constant on geological timescales.

Natural occurrence and production: In nature, scandium is found in trace amounts within various minerals, with thortveitite (Sc2SiO5) being a notable source. Because 45Sc accounts for essentially all natural scandium, the isotope is central to any discussion of scandium’s isotopic composition. Commercial production focuses on extracting scandium metal or compounds from ores, with 45Sc being the stable, nonradioactive isotope present.

Applications: 45Sc is used in scientific research as a stable isotope standard for mass spectrometry and isotopic studies. Its nuclear properties also make it a subject of measurements of magnetic moments and quadrupole moments, and it serves as a probe nucleus in certain solid-state NMR and related experiments.

See also: Isotopes of scandium, Scandium.