Yttrium-89m

Properties and data of the isotope ^89mY.

Contents

Yttrium-89m is an excited nuclear state of the nuclide ⁸⁹Y, characterized by a defined excitation energy of 908.97 keV. Its spin and parity quantum numbers differ from those of the ground state (gs). Simultaneously, this metastable nuclear isomer possesses an independent, experimentally measurable lifetime: decay occurs via an isomeric transition to Y-89 in the ground state with a half-life of approximately 15.663 seconds.

See also: List of individual Yttrium isotopes (and general data sources).

General data

Name of the isotope:Yttrium-89m; Y-89mSymbol:^89mY or 89m39YMass number A:89 (= number of nucleons)Atomic number Z:39 (= number of protons)Neutrons N:50Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.2820512820513 (= neutron-proton ratio)Neutron excess (N-Z):11Excitation energy:908.97(3) keVIsotopic mass:88.9058382(4) u (atomic weight of Yttrium-89m)Nuclide mass:88.8844445 u (calculated nuclear mass without electrons)Mass excess:-87.71115 MeVMass defect:0.83258384799998 u (per nucleus)Nuclear binding energy:775.54685891 MeV (per nucleus)
8.71400965 MeV (average binding energy per nucleon)Half-life:15.663(5) sDecay constant λ:0.044253794328031 s^-1Specific activity α:3.028438443523 × 10⁺²⁰ Bq g^-1
8184968766.2797 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2+Magnetic dipole moment:μ(μ_N) = +6.37(4)Quadrupole moment Q:-0.43(6) barn (100 fm²)Nuclear g-factor:g_l = 1.4155555555556Year of discovery:1951 [1]

Radioactive Decay

Half-life T_½ = 15.663(5) s respectively 1.5663 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	⁸⁹Y	100 %	0.909 MeV

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
⁸⁹Y		stable	1/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 50) and isobaric (same nucleon number A = 89) with Yttrium-89m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 50	Isobar A = 89
28	⁷⁸Ni
29	⁷⁹Cu
30	⁸⁰Zn
31	⁸¹Ga
32	⁸²Ge	⁸⁹Ge
33	⁸³As	⁸⁹As
34	⁸⁴Se	⁸⁹Se
35	⁸⁵Br	⁸⁹Br
36	⁸⁶Kr	⁸⁹Kr
37	⁸⁷Rb	⁸⁹Rb
38	⁸⁸Sr	⁸⁹Sr
39	⁸⁹Y	⁸⁹Y
40	⁹⁰Zr	⁸⁹Zr
41	⁹¹Nb	⁸⁹Nb
42	⁹²Mo	⁸⁹Mo
43	⁹³Tc	⁸⁹Tc
44	⁹⁴Ru	⁸⁹Ru
45	⁹⁵Rh	⁸⁹Rh
46	⁹⁶Pd
47	⁹⁷Ag
48	⁹⁸Cd
49	⁹⁹In
50	¹⁰⁰Sn