Lawrencium

Literature References: Lr; formerly Lw; at. no. 103; valence 3. Man-made radioactive element. No stable nuclides; known isotopes (mass numbers): 253-262. Longest-lived known isotope: 262 (T½ 216 minutes, rel. at. mass 262.110). Prepn of first isotope 257Lr (T½ 0.65 sec, a-emitter): A. Ghiorso et al., Phys. Rev. Lett. 6, 473 (1961). Prepn of isotope originally assigned mass number 257, later changed to 258 (T½ 4.3 seconds, a-emitter) by bombardment of Cf with boron ions: Eskola et al., Phys. Rev. C 4, 632 (1971). Prepn of isotopes including 256Lr (T½ 28 seconds) by irradiating 243Am with 18O ions: Donets et al., At. Energ. 19, 109 (1965), C.A. 64, 1542c (1966). Reviews: C. Keller, The Chemistry of the Transuranium Elements (Verlag Chemie, Weinheim, English Ed., 1971) pp 609-612; Silva, "Trans-Curium Elements" in MTP Int. Rev. Sci.: Inorg. Chem., Ser. One vol. 8, A. G. Maddock, Ed. (University Park Press, Baltimore, 1972) pp 71-105; Ghiorso, Handb. Exp. Pharmakol. 36, 691-715 (1973); Taylor, ibid. 717-738; R. J. Silva in The Chemistry of the Actinide Elements vol. 2, J. J. Katz et al., Eds. (Chapman and Hall, New York, 1986) pp 1099-1103; The Elements Beyond Uranium, G. T. Seaborg, W. D. Loveland, Eds. (John Wiley & Sons, Inc., New York, 1990) p 49-51.