Osmium-185

Properties and data of the isotope ¹⁸⁵Os.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Osmium-185; Os-185Symbol:¹⁸⁵Os or 18576OsMass number A:185 (= number of nucleons)Atomic number Z:76 (= number of protons)Neutrons N:109Isotopic mass:184.9540460(9) u (atomic weight of Osmium-185)Nuclide mass:184.9123582 u (calculated nuclear mass without electrons)Mass excess:-42.80588 MeVMass defect:1.585132276 u (per nucleus)Nuclear binding energy:1476.5412043 MeV (per nucleus)
7.98130381 MeV (average binding energy per nucleon)Separation energy:S_N = 6.62466(27) MeV (first neutron)
S_P = 5.875(4) MeV (first proton)Half-life:93.6(5) dDecay constant λ:8.571086337645 × 10^-8 s^-1Specific activity α:2.805233111303 × 10⁺¹⁴ Bq g^-1
7581.7111116308 Ci g^-1Spin and parity:
(nuclear angular momentum)1/2-Year of discovery:1947

Radioactive Decay

Half-life T_½ = 93.6(5) d respectively 8.087040 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC	¹⁸⁵Re	100 %	1.0131(12) MeV

Parent Nuclides

Direct parent isotope is: ¹⁸⁵Ir.

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
^185m1Os	102.37(11) keV	3.0(4) μs	7/2-
^185m2Os	275.53(12) keV	0.78(5) μs	11/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 109) and isobaric (same nucleon number A = 185) with Osmium-185. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 109	Isobar A = 185
68	¹⁷⁷Er
69	¹⁷⁸Tm
70	¹⁷⁹Yb	¹⁸⁵Yb
71	¹⁸⁰Lu	¹⁸⁵Lu
72	¹⁸¹Hf	¹⁸⁵Hf
73	¹⁸²Ta	¹⁸⁵Ta
74	¹⁸³W	¹⁸⁵W
75	¹⁸⁴Re	¹⁸⁵Re
76	¹⁸⁵Os	¹⁸⁵Os
77	¹⁸⁶Ir	¹⁸⁵Ir
78	¹⁸⁷Pt	¹⁸⁵Pt
79	¹⁸⁸Au	¹⁸⁵Au
80	¹⁸⁹Hg	¹⁸⁵Hg
81	¹⁹⁰Tl	¹⁸⁵Tl
82	¹⁹¹Pb	¹⁸⁵Pb
83	¹⁹²Bi	¹⁸⁵Bi
84	¹⁹³Po
85	¹⁹⁴At
86	¹⁹⁵Rn