Platinum-185m

Properties and data of the isotope ^185mPt.

Contents

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

General data

Name of the isotope:Platinum-185m; Pt-185mSymbol:^185mPt or 185m78PtMass number A:185 (= number of nucleons)Atomic number Z:78 (= number of protons)Neutrons N:107Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.3717948717949 (= neutron-proton ratio)Neutron excess (N-Z):29Excitation energy:103.41(5) keVIsotopic mass:184.960614(28) u (atomic weight of Platinum-185m)Nuclide mass:184.9178293 u (calculated nuclear mass without electrons)Mass excess:-36.68782 MeVMass defect:1.576884508 u (per nucleus)Nuclear binding energy:1468.85845789 MeV (per nucleus)
7.93977545 MeV (average binding energy per nucleon)Half-life:33.0(8) minDecay constant λ:0.00035007433361613 s^-1Specific activity α:1.145759211133 × 10⁺¹⁸ Bq g^-1
30966465.165759 Ci g^-1Spin and parity:
(nuclear angular momentum)1/2-Magnetic dipole moment:μ(μ_N) = + 0.540(9)Nuclear g-factor:g_l = 1.08

Radioactive Decay

Half-life T_½ = 33.0(8) min (minutes) respectively 1.980 × 10³ seconds s.

Decay mode	Daughter	Probability
EC/β⁺	¹⁸⁵Ir	99(1) %
Iso	¹⁸⁵Pt	< 2 %
α	¹⁸¹Os	0.001 %

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
¹⁸⁵Pt		70.9(24) min	9/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 107) and isobaric (same nucleon number A = 185) with Platinum-185m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 107	Isobar A = 185
65	¹⁷²Tb
66	¹⁷³Dy
67	¹⁷⁴Ho
68	¹⁷⁵Er
69	¹⁷⁶Tm
70	¹⁷⁷Yb	¹⁸⁵Yb
71	¹⁷⁸Lu	¹⁸⁵Lu
72	¹⁷⁹Hf	¹⁸⁵Hf
73	¹⁸⁰Ta	¹⁸⁵Ta
74	¹⁸¹W	¹⁸⁵W
75	¹⁸²Re	¹⁸⁵Re
76	¹⁸³Os	¹⁸⁵Os
77	¹⁸⁴Ir	¹⁸⁵Ir
78	¹⁸⁵Pt	¹⁸⁵Pt
79	¹⁸⁶Au	¹⁸⁵Au
80	¹⁸⁷Hg	¹⁸⁵Hg
81	¹⁸⁸Tl	¹⁸⁵Tl
82	¹⁸⁹Pb	¹⁸⁵Pb
83	¹⁹⁰Bi	¹⁸⁵Bi
84	¹⁹¹Po
85	¹⁹²At
86	¹⁹³Rn