Osmium-201

Properties and data of the isotope ²⁰¹Os.

Contents

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

General data

Name of the isotope:Osmium-201; Os-201Symbol:²⁰¹Os or 20176OsMass number A:201 (= number of nucleons)Atomic number Z:76 (= number of protons)Neutrons N:125Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.6447368421053 (= neutron-proton ratio)Neutron excess (N-Z):49Isotopic mass:200.98364(32) u (atomic weight of Osmium-201)Nuclide mass:200.9419522 u (calculated nuclear mass without electrons)Mass excess:-15.23924 MeVMass defect:1.694176932 u (per nucleus)Nuclear binding energy:1578.1156471 MeV (per nucleus)
7.85132163 MeV (average binding energy per nucleon)Separation energy:S_N = 4.53(42) MeV (first neutron)Half-life:160 nsDecay constant λ:4332169.8784997 s^-1Specific activity α:1.30444686187 × 10⁺²⁸ Bq g^-1
3.525532059121 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:2009

Radioactive Decay

Half-life T_½ = 160 ns respectively 1.6 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²⁰¹Ir	?	4.66(36) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 125) and isobaric (same nucleon number A = 201) with Osmium-201. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 125	Isobar A = 201
76	²⁰¹Os	²⁰¹Os
77	²⁰²Ir	²⁰¹Ir
78	²⁰³Pt	²⁰¹Pt
79	²⁰⁴Au	²⁰¹Au
80	²⁰⁵Hg	²⁰¹Hg
81	²⁰⁶Tl	²⁰¹Tl
82	²⁰⁷Pb	²⁰¹Pb
83	²⁰⁸Bi	²⁰¹Bi
84	²⁰⁹Po	²⁰¹Po
85	²¹⁰At	²⁰¹At
86	²¹¹Rn	²⁰¹Rn
87	²¹²Fr	²⁰¹Fr
88	²¹³Ra	²⁰¹Ra
89	²¹⁴Ac
90	²¹⁵Th
91	²¹⁶Pa
92	²¹⁷U