Actinium-215m1

Properties and data of the isotope ²¹⁵Ac.

Content

General data

Name of the isotope:Actinium-215m1; Ac-215m1Symbol: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-215m1)
Excitation energy: 1796.0(9) 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:185(30) nsDecay constant λ:3746741.5165402 s^-1Specific activity α:1.049460705971 × 10⁺²⁸ Bq g^-1
2.836380286408 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)(21/2-)Magnetic dipole moment:μ(μ_N) = 9.66(20)Nuclear g-factor:g_l = 0.92

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-
^215m2Ac	2438+x keV	335(10) ns	(29/2+)

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-215m1. 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