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Isotopes of hassium

Hassium (Hs) has no stable isotopes. A standard atomic mass cannot be given.

Hassium has also been called hahnium, sergenium, and eka-osmium.

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
²⁶³Hs	108	155	263.12856(37)#	1# ms	7/2+#
²⁶⁴Hs	108	156	264.12839(5)	540(300) µs	0+
²⁶⁵Hs	108	157	265.13009(15)#	2.1(3) ms [2.0(+3-2) ms]	9/2+#
^265mHs	300(70) keV			780(150) µs [0.75(+17-12) ms]	3/2+#
²⁶⁶Hs	108	158	266.13010(31)#	2.7(10) ms [2.3(+13-6) ms]	0+
²⁶⁷Hs	108	159	267.13179(11)#	32(15) ms	3/2+#
²⁶⁸Hs	108	160	268.13216(44)#	2# s	0+
²⁶⁹Hs	108	161	269.13406(13)#	27(17) s
²⁷⁰Hs	108	162	270.13465(31)#	3.6(+8-14) s	0+
²⁷¹Hs	108	163	271.13766(36)#	40# s
²⁷²Hs	108	164	272.13905(62)#	40# s	0+
²⁷³Hs	108	165	273.14199(89)#	50# s	(3/2+)#
²⁷⁴Hs	108	166	274.14313(70)#	1# min	0+
²⁷⁵Hs	108	167	275.14595(77)#	0.15(+27-6) s
²⁷⁶Hs	108	168	276.14721(89)#	1# h	0+
²⁷⁷Hs	108	169	277.14984(78)#	40(30) min	3/2+#

Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
- Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
- National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
- David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.