= Chlorine-37
<Chlorine-37> is a stable <isotope> of <chlorine> containing $17$ <protons> and $20$ <neutrons>. Its <mass number> is $37$, which is distinct from its measured relative <atomic mass> and from the average atomic weight of a natural chlorine sample.
NIST's representative isotopic composition lists about $24.24\%$ chlorine-37 and $75.76\%$ chlorine-35.<Atomic Weights and Isotopic Compositions for All Elements by National Institute of Standards and Technology>[Chlorine entries: masses 35 and 37 and their representative abundances]{ref} The two stable isotopes explain characteristic peaks separated by two nominal mass units in chlorine-containing <mass spectra>. Exact peak patterns also depend on the number of chlorine <atoms> and other isotopes present.
Back to article page
