Isotopes of lawrencium

Lawrencium (Lr) has no stable isotopes. There are eleven known radioisotopes from ²⁵²Lr to ²⁶²Lr, and 1 isomer (^253mLr). The isotope with the longest half-life is ²⁶²Lr with a half-life of 216 minutes. Heavier isotopes are expected to have longer half-lives. A standard atomic mass cannot be given as lawrencium is artificial.

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)	daughter isotope(s)	nuclear spin
	excitation energy
252Lr	103	149	252.09537(27)#	390(90) ms [0.36(+11-7) s]	α (90%)	248Md
					β+ (10%)	252No
					SF (1%)	(various)
253Lr	103	150	253.09521(24)#	580(70) ms [0.57(+7-6) s]	α (90%)	249Md	(7/2-)
					SF (9%)	(various)
					β+ (1%)	253No
253mLr	30(100)# keV			1.5(3) s [1.5(+3-2) s]			(1/2-)
254Lr	103	151	254.09645(36)#	13(3) s	α (78%)	250Md
					β+ (22%)	254No
					SF (.1%)	(various)
255Lr	103	152	255.09668(22)#	22(4) s	α (69%)	251Md	7/2-#
					β+ (30%)	255No
					SF (1%)	(various)
256Lr	103	153	256.09863(24)#	27(3) s	α (80%)	252Md
					β+ (20%)	256No
					SF (.01%)	(various)
257Lr	103	154	257.09956(22)#	646(25) ms	α (99.99%)	253Md	9/2+#
					β+ (.01%)	257No
					SF (.001%)	(various)
258Lr	103	155	258.10181(11)#	4.1(3) s	α (95%)	254Md
					β+ (5%)	258No
259Lr	103	156	259.10290(8)#	6.2(3) s	α (77%)	255Md	9/2+#
					SF (23%)	(various)
					β+ (.5%)	259No
260Lr	103	157	260.10550(12)#	2.7 min	α (75%)	256Md
					β+ (15%)	260No
					SF (10%)	(various)
261Lr	103	158	261.10688(22)#	44 min	SF	(various)
					α (rare)	257Md
262Lr	103	159	262.10963(22)#	216 min	β+	262No
					α (rare)	258Md

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:
  • G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. doi:10.1016/j.nuclphysa.2003.11.001.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• Isotopic compositions and standard atomic masses from:
  • J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  • M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. {{cite journal}}: Unknown parameter |laysummary= ignored (help)
• Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
  • G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. doi:10.1016/j.nuclphysa.2003.11.001.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  • National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005. {{cite web}}: Check date values in: |accessdate= (help)
  • N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide (ed.). CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0849304859. {{cite book}}: Unknown parameter |nopp= ignored (|no-pp= suggested) (help)