Isotopes of meitnerium

Meitnerium (Mt) has no stable isotopes, due to its high radioactivity and due to its status as an transactinide. A standard atomic mass cannot be given.

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)
	excitation energy
265Mt	109	156	265.13615(50)#	2# ms
266Mt	109	157	266.13730(37)#	1.2(4) ms
266mMt	1230(80) keV			6(3) ms
267Mt	109	158	267.13731(58)#	10# ms
268Mt	109	159	268.13873(34)#	21(+8-5) ms	5+#,6+#
268mMt	0+X keV			0.07(+10-3) s
269Mt	109	160	269.13906(59)#	200# ms
270Mt	109	161	270.14066(58)#	2# s
271Mt	109	162	271.14114(61)#	5# s
272Mt	109	163	272.14374(52)#	10# s
273Mt	109	164	273.14491(55)#	20# s
274Mt	109	165	274.14749(60)#	20# s
275Mt	109	166	275.14865(64)#	9.7(+460-44) ms
276Mt	109	167	276.15116(73)#	0.72(+87-25) s
277Mt	109	168	277.15242(95)#	1# min
278Mt	109	169	278.15481(90)#	30# min
279Mt	109	170	279.15619(77)#	6# min

Notes

• 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.

References

• 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.