Rhodium-99m

Properties and data of the isotope ⁹⁹Rh.

Content

General data

Name of the isotope:Rhodium-99m; Rh-99mSymbol:⁹⁹Rh or 9945RhMass number A:99 (= number of nucleons)Atomic number Z:45 (= number of protons)Neutrons N:54Isotopic mass:98.908125(7) u (atomic weight of Rhodium-99m)
Excitation energy: 64.4(5) keVNuclide mass:98.8834402 u (calculated nuclear mass without electrons)Mass excess:-85.58101 MeVMass defect:0.91190690400001 u (per nucleus)Nuclear binding energy:849.43580963 MeV (per nucleus)
8.58015969 MeV (average binding energy per nucleon)Half-life:4.7(1) hDecay constant λ:4.096614542316 × 10^-5 s^-1Specific activity α:2.517386716601 × 10⁺¹⁷ Bq g^-1
6803747.8827068 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2+Magnetic dipole moment:μ(μ_N) = 5.62(6)Nuclear g-factor:g_l = 1.2488888888889

Radioactive Decay

Half-life T_½ = 4.7(1) h (hours) respectively 1.6920 × 10⁴ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	⁹⁹Ru	> 99.84 %
Iso	⁹⁹Rh	< 0.16 %

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
⁹⁹Rh		16.1(2) d	1/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 54) and isobaric (same nucleon number A = 99) with Rhodium-99m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 54	Isobar A = 99
30	⁸⁴Zn
31	⁸⁵Ga
32	⁸⁶Ge
33	⁸⁷As
34	⁸⁸Se
35	⁸⁹Br
36	⁹⁰Kr	⁹⁹Kr
37	⁹¹Rb	⁹⁹Rb
38	⁹²Sr	⁹⁹Sr
39	⁹³Y	⁹⁹Y
40	⁹⁴Zr	⁹⁹Zr
41	⁹⁵Nb	⁹⁹Nb
42	⁹⁶Mo	⁹⁹Mo
43	⁹⁷Tc	⁹⁹Tc
44	⁹⁸Ru	⁹⁹Ru
45	⁹⁹Rh	⁹⁹Rh
46	¹⁰⁰Pd	⁹⁹Pd
47	¹⁰¹Ag	⁹⁹Ag
48	¹⁰²Cd	⁹⁹Cd
49	¹⁰³In	⁹⁹In
50	¹⁰⁴Sn	⁹⁹Sn
51	¹⁰⁵Sb
52	¹⁰⁶Te