Osmium-186

Properties and data of the isotope ¹⁸⁶Os.

Content

General data

Name of the isotope:Osmium-186; Os-186Symbol:¹⁸⁶Os or 18676OsMass number A:186 (= number of nucleons)Atomic number Z:76 (= number of protons)Neutrons N:110Isotopic mass:185.95384(1) u (atomic weight of Osmium-186)Nuclide mass:185.9121522 u (calculated nuclear mass without electrons)Mass excess:-42.99776 MeVMass defect:1.594003192 u (per nucleus)Nuclear binding energy:1484.80440933 MeV (per nucleus)
7.9828194 MeV (average binding energy per nucleon)Separation energy:S_N = 8.2654(9) MeV (first neutron)
S_P = 6.4699(8) MeV (first proton)Half-life:2.0(11) × 10¹⁵ aDecay constant λ:1.098977645484 × 10^-23 s^-1Specific activity α:0.035774044232589 Bq g^-1
9.668660603402 × 10^-13 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:5.3909(17) femtometer fmYear of discovery:1931

Radioactive Decay

Half-life T_½ = 2.0(11) × 10¹⁵ a respectively 6.3072 × 10²² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁸²W	100 %	2.8212(9) MeV

Parent Nuclides

Direct parent isotopes are: ¹⁸⁶Ir, ¹⁸⁶Re, ¹⁹⁰Pt.

Occurrence

Comparison of the natural Osmium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Osmium Isotopic mixture	190.23 u	100 %
Isotope ¹⁸⁴Os	183.952489(9) u	0.02(1) %	5.6 × 10¹³ a	0+
Isotope ¹⁸⁶Os	185.95384(1) u	1.59(3) %	2.0(11) × 10¹⁵ a	0+
Isotope ¹⁸⁷Os	186.95575(1) u	1.96(2) %	stable	1/2-
Isotope ¹⁸⁸Os	187.95584(1) u	13.24(8) %	stable	0+
Isotope ¹⁸⁹Os	188.95814(2) u	16.15(5) %	stable	3/2-
Isotope ¹⁹⁰Os	189.95844(2) u	26.26(2) %	stable	0+
Isotope ¹⁹²Os	191.96148(2) u	40.78(19) %	stable	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 110) and isobaric (same nucleon number A = 186) with Osmium-186. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 110	Isobar A = 186
69	¹⁷⁹Tm
70	¹⁸⁰Yb
71	¹⁸¹Lu	¹⁸⁶Lu
72	¹⁸²Hf	¹⁸⁶Hf
73	¹⁸³Ta	¹⁸⁶Ta
74	¹⁸⁴W	¹⁸⁶W
75	¹⁸⁵Re	¹⁸⁶Re
76	¹⁸⁶Os	¹⁸⁶Os
77	¹⁸⁷Ir	¹⁸⁶Ir
78	¹⁸⁸Pt	¹⁸⁶Pt
79	¹⁸⁹Au	¹⁸⁶Au
80	¹⁹⁰Hg	¹⁸⁶Hg
81	¹⁹¹Tl	¹⁸⁶Tl
82	¹⁹²Pb	¹⁸⁶Pb
83	¹⁹³Bi	¹⁸⁶Bi
84	¹⁹⁴Po	¹⁸⁶Po
85	¹⁹⁵At
86	¹⁹⁶Rn