63Cu

63Cu is a stable isotope of copper with mass number 63. It is one of the two stable copper isotopes, the other being 65Cu. In natural copper, about 69.2% is 63Cu and about 30.8% is 65Cu, which gives a standard atomic weight of copper of approximately 63.546.

The nucleus of 63Cu has a nonzero spin, I = 3/2, and a measurable electric quadrupole moment. These properties make 63Cu observable in nuclear magnetic resonance (NMR) and subject to quadrupolar interactions in solid materials. Because isotopes of the same element share identical chemical behavior, 63Cu and 65Cu participate in chemical reactions and form compounds in the same way.

63Cu does not undergo radioactive decay, and it occurs naturally in copper metal, alloys, and a wide range of copper-containing compounds. Its stable nature and relatively high natural abundance make it useful in isotopic studies. The 63Cu/65Cu isotopic pair is commonly employed in isotope ratio analyses in geology, archaeology, and environmental science to investigate copper sources, processing, and provenance. It is also used in solid-state NMR and related spectroscopic investigations of copper-containing materials, where the nuclear spin properties of 63Cu provide useful spectroscopic information.

Overall, 63Cu is a stable, NMR-active isotope that contributes to the average properties of natural copper and serves as a practical tool in isotopic and materials research.