Dubnium

Literature References: Db, Ha, Ns, Unp; at. no. 105. Group VB(5). No stable nuclides. Prepn of a-emitting 260105 isotope (T½ 1.6±0.3 sec) by 249Cf (15N,4n): A. Ghiorso et al., Phys. Rev. Lett. 24, 1498 (1970). Prepn of 261105 isotope (decay by spontaneous fission, T½ 1.8 ±0.6 sec) by 243Am (22Ne,4n): G. N. Flerov et al., At. Energ. 29, 243 (1970); eidem, Nucl. Phys. A 160, 181 (1971); eidem, Proc. Int. Conf. Heavy Ion Phys. 1971 pp 125-143, C.A. 80, 139758y (1974). Prepn of a-emitting isotopes 261105 (T½ 1.7 sec) by 249Bk (16O,4n) or by 250Cf (15N,4n); 262105 (T½ 40.0 ±10 sec, longest-lived known isotope, rel. at. mass 262.1144) by 249Bk(18O,5n): A. Ghiorso et al., Phys. Rev. C4, 1850 (1971); and revised T½ 34.1 ±4.6 sec for 262105: C. E. Bemis, Jr. et al., Phys. Rev. Lett. 39, 1246 (1977). Discussion of conflicting claims of discovery: Holcomb, Science 168, 810 (1970); G. N. Flerov, ibid. 170, 15 (1970); A. Ghiorso, ibid. 171, 127 (1971). Solution chemistry: K. E. Gregorich et al., Radiochim. Acta 43, 223 (1988); M. K. Gober et al., ibid. 57, 77 (1992); and identification of 263105 isotope (T½ 27 sec, a-emitter) by 249Bk(18O,4n): M. Schädel et al., ibid. 85. Reviews of history, prepn and properties: C. Keller, The Chemistry of the Transuranium Elements (Verlag Chemie, Weinheim, English Ed., 1971) pp 619-622; 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; 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 1106-1109; E. K. Hyde et al., Radiochim. Acta 42, 57-102 (1987); Transfermium Working Group, Pure Appl. Chem. 65, 1757-1814 (1993). Review of chemistry: D. C. Hoffman, Proc. Robert A. Welch Found. Conf. on Chem. Res., XXXIV, Fifty Years with Transuranium Elements (Houston, Texas, 1990) pp 255-276.