Platinum-185

Properties and data of the isotope ¹⁸⁵Pt.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Platinum-185; Pt-185Symbol:¹⁸⁵Pt or 18578PtMass number A:185 (= number of nucleons)Atomic number Z:78 (= number of protons)Neutrons N:107Isotopic mass:184.960614(28) u (atomic weight of Platinum-185)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)Separation energy:S_N = 7.43(3) MeV (first neutron)
S_P = 4.37(4) MeV (first proton)Half-life:70.9(24) minDecay constant λ:0.00016294009886223 s^-1Specific activity α:5.3328707993 × 10⁺¹⁷ Bq g^-1
14413164.322568 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2+Magnetic dipole moment:μ(μ_N) = - 0.774(14)Quadrupole moment Q:+ 4.30(5) barn (100 fm²)Nuclear g-factor:g_l = -0.172Charge radius:5.4148(28) femtometer fmYear of discovery:1960

Radioactive Decay

Half-life T_½ = 70.9(24) min (minutes) respectively 4.254 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	¹⁸⁵Ir	< 100 %	3.65(4) MeV

Parent Nuclides

Direct parent isotope is: ¹⁸⁵Au.

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
^185mPt	103.41(5) keV	33.0(8) min	1/2-

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-185. 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