Astatine-193m2

Properties and data of the isotope ¹⁹³At.

Content

General data

Name of the isotope:Astatine-193m2; At-193m2Symbol:¹⁹³At or 19385AtMass number A:193 (= number of nucleons)Atomic number Z:85 (= number of protons)Neutrons N:108Isotopic mass:192.999928(23) u (atomic weight of Astatine-193m2)
Excitation energy: 39(7) keVNuclide mass:192.9533043 u (calculated nuclear mass without electrons)Mass excess:-0.06707 MeVMass defect:1.601010648 u (per nucleus)Nuclear binding energy:1491.33181255 MeV (per nucleus)
7.72710784 MeV (average binding energy per nucleon)Half-life:ca. 27 msDecay constant λ:25.672117798516 s^-1Specific activity α:8.052141122685 × 10⁺²² Bq g^-1
2176254357482.5 Ci g^-1Spin and parity:
(nuclear angular momentum)(13/2+)

Radioactive Decay

Half-life T_½ = ca. 27 ms respectively 2.7 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁸⁹Bi	24(10) %
Iso	¹⁹³At	76(10) %

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
¹⁹³At		ca. 28 ms	(1/2+)
^193m1At	5(10) kev	21(5) ms	(7/2-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 108) and isobaric (same nucleon number A = 193) with Astatine-193m2. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 108	Isobar A = 193
66	¹⁷⁴Dy
67	¹⁷⁵Ho
68	¹⁷⁶Er
69	¹⁷⁷Tm
70	¹⁷⁸Yb
71	¹⁷⁹Lu
72	¹⁸⁰Hf
73	¹⁸¹Ta	¹⁹³Ta
74	¹⁸²W	¹⁹³W
75	¹⁸³Re	¹⁹³Re
76	¹⁸⁴Os	¹⁹³Os
77	¹⁸⁵Ir	¹⁹³Ir
78	¹⁸⁶Pt	¹⁹³Pt
79	¹⁸⁷Au	¹⁹³Au
80	¹⁸⁸Hg	¹⁹³Hg
81	¹⁸⁹Tl	¹⁹³Tl
82	¹⁹⁰Pb	¹⁹³Pb
83	¹⁹¹Bi	¹⁹³Bi
84	¹⁹²Po	¹⁹³Po
85	¹⁹³At	¹⁹³At
86	¹⁹⁴Rn	¹⁹³Rn