Argon-49

Properties and data of the isotope ⁴⁹Ar.

Content

General data

Name of the isotope:Argon-49; Ar-49Symbol:⁴⁹Ar or 4918ArMass number A:49 (= number of nucleons)Atomic number Z:18 (= number of protons)Neutrons N:31Isotopic mass:48.98155(43) u (atomic weight of Argon-49)Nuclide mass:48.9716757 u (calculated nuclear mass without electrons)Mass excess:-17.18606 MeVMass defect:0.427912972 u (per nucleus)Nuclear binding energy:398.59836594 MeV (per nucleus)
8.13466053 MeV (average binding energy per nucleon)Separation energy:S_N = 2.98(50) MeV (first neutron)
S_P = 20.20(64) MeV (first proton)Half-life:170(50) msDecay constant λ:4.077336356235 s^-1Specific activity α:5.115477889705 × 10⁺²² Bq g^-1
1382561591812.4 Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:1989

Radioactive Decay

Half-life T_½ = 170(50) ms respectively 1.70 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁴⁹K	35(20) %	12.42(40) MeV
β^-, n	⁴⁸K	65(20) %	7.02(40) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 31) and isobaric (same nucleon number A = 49) with Argon-49. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 31	Isobar A = 49
15	⁴⁶P
16	⁴⁷S	⁴⁹S
17	⁴⁸Cl	⁴⁹Cl
18	⁴⁹Ar	⁴⁹Ar
19	⁵⁰K	⁴⁹K
20	⁵¹Ca	⁴⁹Ca
21	⁵²Sc	⁴⁹Sc
22	⁵³Ti	⁴⁹Ti
23	⁵⁴V	⁴⁹V
24	⁵⁵Cr	⁴⁹Cr
25	⁵⁶Mn	⁴⁹Mn
26	⁵⁷Fe	⁴⁹Fe
27	⁵⁸Co	⁴⁹Co
28	⁵⁹Ni	⁴⁹Ni
29	⁶⁰Cu
30	⁶¹Zn
31	⁶²Ga
32	⁶³Ge
33	⁶⁴As
34	⁶⁵Se
35	⁶⁶Br
36	⁶⁷Kr