Hassium-265

Properties and data of the isotope ²⁶⁵Hs.

Contents

General data

Name of the isotope:Hassium-265; Hs-265Symbol:²⁶⁵Hs or 265108HsMass number A:265 (= number of nucleons)Atomic number Z:108 (= number of protons)Neutrons N:157Isotopic mass:265.129792(26) u (atomic weight of Hassium-265)Nuclide mass:265.0705551 u (calculated nuclear mass without electrons)Mass excess:120.90047 MeVMass defect:2.075703268 u (per nucleus)Nuclear binding energy:1933.50513992 MeV (per nucleus)
7.29624581 MeV (average binding energy per nucleon)Separation energy:S_N = 6.73(4) MeV (first neutron)
S_P = 2.45(18) MeV (first proton)Half-life:2.0 msDecay constant λ:346.57359027997 s^-1Specific activity α:7.875905581132 × 10⁺²³ Bq g^-1
21286231300357 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2+Year of discovery:1984

Radioactive Decay

Half-life T_½ = 2.0 ms respectively 2 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁶¹Sg	ca. 100 %	10.470(15) MeV
SZ	div	≤ 1 %

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
^265mHs	300 keV	0.75 ms	3/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 157) and isobaric (same nucleon number A = 265) with Hassium-265. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 157	Isobar A = 265
97	²⁵⁴Bk
98	²⁵⁵Cf
99	²⁵⁶Es
100	²⁵⁷Fm
101	²⁵⁸Md
102	²⁵⁹No
103	²⁶⁰Lr	²⁶⁵Lr
104	²⁶¹Rf	²⁶⁵Rf
105	²⁶²Db	²⁶⁵Db
106	²⁶³Sg	²⁶⁵Sg
107	²⁶⁴Bh	²⁶⁵Bh
108	²⁶⁵Hs	²⁶⁵Hs
109	²⁶⁶Mt
110	²⁶⁷Ds