Isotopes of dubnium

Dubnium (Db) has no stable isotopes. A standard atomic mass cannot be given, though the atomic mass of the most stable isotope is approx. 262.11.

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
255Db	105	150	255.10740(45)#	1.7(5) s [1.6(+6-4) s]
256Db	105	151	256.10813(31)#	1.9(4) s [1.6(+5-3) s]
257Db	105	152	257.10772(24)#	1.53(17) s [1.50(+19-15) s]	(9/2+)
257mDb	100(100)# keV			790(130) ms [0.76(+15-11) s]	(1/2-)
258Db	105	153	258.10923(37)#	4.5(6) s
258mDb	60(100)# keV			20(10) s
259Db	105	154	259.10961(23)#	0.51(16) s
260Db	105	155	260.11130(25)#	1.52(13) s
261Db	105	156	261.11206(25)#	1.8(4) s
262Db	105	157	262.11408(20)#	35(5) s
263Db	105	158	263.11499(18)#	29(9) s [27(+10-7) s]
264Db	105	159	264.11740(25)#	3# min
265Db	105	160	265.1186(3)#	15# min
266Db	105	161	266.12103(39)#	20# min
267Db	105	162	267.12238(50)#	73(+350-33) min
268Db	105	163	268.12545(57)#	32(+11-7) h
269Db	105	164	269.12746(83)#	3# h
270Db	105	165	270.13071(77)#	1# h

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.