Actinium-215m2

Properties and data of the isotope ²¹⁵Ac.

Content

General data

Name of the isotope:Actinium-215m2; Ac-215m2Symbol:²¹⁵Ac or 21589AcMass number A:215 (= number of nucleons)Atomic number Z:89 (= number of protons)Neutrons N:126Isotopic mass:215.006474(13) u (atomic weight of Actinium-215m2)
Excitation energy: 2438+x keVNuclide mass:214.9576566 u (calculated nuclear mass without electrons)Mass excess:6.03049 MeVMass defect:1.781733264 u (per nucleus)Nuclear binding energy:1659.67384502 MeV (per nucleus)
7.71941323 MeV (average binding energy per nucleon)Half-life:335(10) nsDecay constant λ:2069096.061373 s^-1Specific activity α:5.795529271780 × 10⁺²⁷ Bq g^-1
1.566359262643 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)(29/2+)Magnetic dipole moment:μ(μ_N) = 15.13(30)Nuclear g-factor:g_l = 1.0434482758621

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
²¹⁵Ac		0.17(1) s	9/2-
^215m1Ac	1796.0(9) keV	185(30) ns	(21/2-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 126) and isobaric (same nucleon number A = 215) with Actinium-215m2. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 126	Isobar A = 215
76	²⁰²Os
77	²⁰³Ir
78	²⁰⁴Pt
79	²⁰⁵Au
80	²⁰⁶Hg	²¹⁵Hg
81	²⁰⁷Tl	²¹⁵Tl
82	²⁰⁸Pb	²¹⁵Pb
83	²⁰⁹Bi	²¹⁵Bi
84	²¹⁰Po	²¹⁵Po
85	²¹¹At	²¹⁵At
86	²¹²Rn	²¹⁵Rn
87	²¹³Fr	²¹⁵Fr
88	²¹⁴Ra	²¹⁵Ra
89	²¹⁵Ac	²¹⁵Ac
90	²¹⁶Th	²¹⁵Th
91	²¹⁷Pa	²¹⁵Pa
92	²¹⁸U	²¹⁵U
93	²¹⁹Np