Chlorine-33

Properties and data of the isotope ³³Cl.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Chlorine-33 is a radioisotope of the chemical element chlorine, which has 16 neutrons in its atomic nucleus in addition to the element-specific 17 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 33. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ³³Cl is exclusively for academic purposes and experimental research.

The isotope was first observed when highly purified sulfur templates were irradiated with deuterons (hydrogen-2 nuclei) of an energy of 8 MeV [1, (1940)]:

³²S(d,n)³³Cl.

Chlorine-33 can also be produced by irradiating sulfur-32 with helium-3 nuclei of an energy of 9.68 MeV according to the following proton transfer reaction [2]:

³²S(³He, d)³³Cl.

See also: List of individual Chlorine isotopes (and general data sources).

General data

Name of the isotope:Chlorine-33; Cl-33Symbol:³³Cl or 3317ClMass number A:33 (= number of nucleons)Atomic number Z:17 (= number of protons)Neutrons N:16Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):0.94117647058824 (= neutron-proton ratio)Neutron excess (N-Z):-1Isotopic mass:32.9774520(4) u (atomic weight of Chlorine-33)Nuclide mass:32.9681263 u (calculated nuclear mass without electrons)Mass excess:-21.00333 MeVMass defect:0.2942122 u (per nucleus)Nuclear binding energy:274.05689903 MeV (per nucleus)
8.30475452 MeV (average binding energy per nucleon)Separation energy:S_N = 1.57400(7) MeV (first neutron)
S_P = 2.2768(4) MeV (first proton)Half-life:2.5059(23) sDecay constant λ:0.27660608187076 s^-1Specific activity α:5.205502461690 × 10⁺²¹ Bq g^-1
140689255721.36 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2+Magnetic dipole moment:μ(μ_N) = + 0.7547(3)Nuclear g-factor:g_l = 0.50313333333333Mirror nucleus:Sulfur-33Year of discovery:1940

Radioactive Decay

Half-life T_½ = 2.5059(23) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	³³S	100 %	5.5825(4) MeV

Parent Nuclides

Direct parent isotopes are: ³³Ar, ³⁵Ca.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 16) and isobaric (same nucleon number A = 33) with Chlorine-33. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 16	Isobar A = 33
5	²¹B
6	²²C
7	²³N
8	²⁴O
9	²⁵F
10	²⁶Ne	³³Ne
11	²⁷Na	³³Na
12	²⁸Mg	³³Mg
13	²⁹Al	³³Al
14	³⁰Si	³³Si
15	³¹P	³³P
16	³²S	³³S
17	³³Cl	³³Cl
18	³⁴Ar	³³Ar
19	³⁵K	³³K
20	³⁶Ca
21	³⁷Sc
22	³⁸Ti