90Zr

90Zr, or zirconium-90, is a stable isotope of the element zirconium (atomic number 40). Its nucleus contains 40 protons and 50 neutrons, giving it a mass number of 90. The ground-state spin and parity are 0+, and its atomic mass is about 89.9047 amu.

Natural zirconium consists of several isotopes, with 90Zr accounting for roughly half of the element’s natural abundance. The other stable isotopes are 91Zr, 92Zr, 94Zr, and 96Zr, present in smaller fractions. Because 90Zr is the most abundant stable isotope, it is often used as a reference in isotopic analyses and as a target in nuclear physics experiments.

From a nuclear-structure perspective, 90Zr has a neutron number N = 50, which is a magic number in the nuclear shell model. This closed neutron shell contributes to its relative stability and makes 90Zr a convenient benchmark for studying nuclear structure and reaction mechanisms.

Production and applications: 90Zr occurs naturally and can be enriched or isolated for experimental use. It is widely employed as a stable target in nuclear physics research and as a convenient reference isotope in analytical chemistry and materials science related to zirconium-containing compounds. Its high natural abundance and stability also make it relevant in discussions of zirconium’s isotopic composition in geochemical investigations.