35Cln

35Cln is the neutral isotope of chlorine with a mass number of 35. It consists of 17 protons and 18 neutrons in the nucleus. As a stable isotope, 35Cln does not undergo radioactive decay on observable timescales and occurs naturally in chlorine-bearing substances.

Nuclear and chemical properties are defined by its composition rather than its isotope identity. The nucleus has Z = 17, N = 18, and total angular momentum I = 3/2. Chlorine-35 is one of the two stable chlorine isotopes, the other being 37Cl. Because 35Cln is a quadrupolar nucleus (I = 3/2), its nuclear magnetic resonance signals are often broader and more complex than those of spin-1/2 nuclei, which affects high-resolution NMR studies but can still yield information about local structure and symmetry in solids and liquids. The chemical behavior of chlorine is effectively the same for 35Cln as for 37Cl since chemistry is governed by electronic structure, not by small mass differences.

Natural abundance and isotope effects are relevant for analytical measurements. 35Cl has an abundance of about 75.8%, while 37Cl accounts for about 24.2%. Because isotopes exhibit nearly identical chemistry, compounds containing 35Cl and 37Cl differ only in mass, which can produce tiny kinetic or vibrational isotope effects in some contexts.

Occurrence and applications are widespread in chlorine-bearing materials, including seawater and halite. 35Cln is a common baseline for isotope-ratio studies and environmental tracing, and it forms part of the standard isotope mix used in chlorine-related analyses alongside 37Cl. For dating or radiometric applications, the radioactive isotope 36Cl is used instead of 35Cln.