Argon-33

Properties and data of the isotope ³³Ar.

Content

General data

Name of the isotope:Argon-33; Ar-33Symbol:³³Ar or 3318ArMass number A:33 (= number of nucleons)Atomic number Z:18 (= number of protons)Neutrons N:15Isotopic mass:32.9899255(4) u (atomic weight of Argon-33)Nuclide mass:32.9800512 u (calculated nuclear mass without electrons)Mass excess:-9.38434 MeVMass defect:0.280898816 u (per nucleus)Nuclear binding energy:261.65556171 MeV (per nucleus)
7.92895642 MeV (average binding energy per nucleon)Separation energy:S_N = 15.2553(18) MeV (first neutron)
S_P = 3.3386(7) MeV (first proton)Half-life:173.0(20) msDecay constant λ:4.0066311015026 s^-1Specific activity α:7.540155270953 × 10⁺²² Bq g^-1
2037879802960.5 Ci g^-1Spin and parity:
(nuclear angular momentum)1/2+Magnetic dipole moment:μ(μ_N) = - 0.723(6)Nuclear g-factor:g_l = -1.446Charge radius:3.3438(57) femtometer fmMirror nucleus:Phosphorus-33Year of discovery:1964

Radioactive Decay

Half-life T_½ = 173.0(20) ms respectively 1.730 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	³³Cl	61.3(10) %	11.61896 MeV
ε, p	³²S	38.7(10) %	9.343 MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 15) and isobaric (same nucleon number A = 33) with Argon-33. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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