THE TRANSURANIUM ELEMENTS

The chemical elements are the building blocks of nature. All substances are combinations of these elements. There are (as of 2005) 113 known chemical elements with the heaviest naturally occurring element being uranium (Z = 92). The 22 heaviest chemical elements, the transuranium elements, are manmade. The story of their synthesis, their properties, their impact on chemistry and physics, and their importance to society is fascinating. This story is of particular importance to nuclear chemistry because most of our knowledge of these elements and their properties comes from the work of nuclear chemists, and such work continues to be a major area of nuclear chemical research. One of us (GTS) has been intimately involved in the discovery and characterization of these transuranium elements. 

A copy of the periodic table produced in 1930 would have shown ninety elements. All of the elements from hydrogen through uranium were known with the exception of elements 43 and 61. Elements 43 (technetium) and 61 (promethium) were produced artificially, but that still did not mean that the periodic table ended with uranium. By the time promethium had been discovered, the first elements lying beyond uranium—the transuranium elements— were beginning to be discovered. 

A copy of the periodic table produced in 2012 shows a total of 118 elements. The discoveries of elements 93 through 112,114 and 116 have been sufficiently confirmed that they have been allowed to give names to their discoveries. 

and 118 have been reported, their discoveries are waiting independent confirmation from other laboratories. When experiments confirm that these elements really have been made, then their discoverers will be allowed to recommend names and symbols for them. 

There are twenty-eight elements that do not occur in nature and have been produced artificially. That constitutes almost one-quarter of the periodic table  

The following list gives the atomic numbers of transuranium elements 93-112,114, and 116, their names and symbols, and the people or places after whom they have been named  

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Special techniques for experimentation with the actinide elements other than Th and U have been devised because of the potential health ha2ard to the experimenter and the small amounts available (15). In addition, iavestigations are frequently carried out with the substance present ia very low coaceatratioa as a radioactive tracer. Such procedures coatiaue to be used to some exteat with the heaviest actinide elements, where only a few score atoms may be available they were used ia the earHest work for all the transuranium elements. Tracer studies offer a method for obtaining knowledge of oxidation states, formation of complex ions, and the solubiHty of various compounds. These techniques are not appHcable to crystallography, metallurgy, and spectroscopic studies. 

G. T. Seaborg,. J. Katz, and W. M. Manning eds.. The Transuranium Elements Research Papers, National Nuclear Energy Series, Div. IV, 14B, McGraw-Hill Book Co., Inc., New York, 1949. 

G. T. Seaborg, The Transuranium Elements, Addison-Wesley Publishing Co., Reading, Mass., 1958. 

C. KeUer, in The Chemisty of the Transuranium Elements, Vedag Chemie, Weinheim, Germany, 1971, Chapt. XIV. 

A further group of elements, the transuranium elements, has been synthesized by artificial nuclear reactions in the period from 1940 onwards their relation to the periodic table is discussed fully in Chapter 31 and need not be repeated here. Perhaps even more striking today are the predictions, as yet unverified, for the properties of the currently non-existent superheavy elements.Elements up to lawrencium (Z = 103) are actinides (5f) and the 6d transition series starts with element 104. So far only elements 104-112 have been synthesized, ) and, because there is as yet no agreement on trivial names for some of these elements (see pp. 1280-1), they are here referred to by their atomic numbers. A systematic naming scheme was approved by lUPAC in 1977 but is not widely used by researchers in the field. It involves the use of three-letter symbols derived directly from the atomic number by using the... 

The transuranium elements must all be prepared artificially. In the case of plutonium about 1200 tonnes have so far been produced worldwide, about three-quarters of it in civilian reactors. 

Apart from g Pu, which is a nuclear fuel and explosive, the transuranium elements have in the past been produced mainly for research purposes. A number of specialized applications, however, have led to more widespread uses. I Pu (produced by neutron bombardment of I Np to form 93 Np which decays by jS-emission to 94Pu) is a compact heat source (0.56 Wg as it decays by a-emission) which, in conjunction with PbTe thermoelectric elements, for instance, provides a stable and totally reliable source of electricity with no moving parts. It has been... 

E. M. McMillan and G. T. Seaborg (Berkeley) discoveries in the chemistry of the transuranium elements. 

Seaborg, G. T. "The Transuranium Elements Products of Modern Alchemy," Dowden, Hutchinson and Ross, Inc., Stroudsburg, Pennsylvania, 1978, 488 pp. 

Keller, C. "The Chemistry of the Transuranium Elements," Verlag Chemie GmbH, Weinheim/Bergstr., Germany, 1971, p. 229. 

The transuranium elements are the elements following uranium in the periodic table. The elements from rutherfordium (Rf, Z = 104) through meitnerium... 

A77. C. Keller, The Chemistry of the Transuranium Elements. Verlag Chemie, Weinheim, 1971. Chapter 8, Organometallic compounds of the actinides, pp. 187-193 (36). Not as comprehensive as reference 4.39. 

Jaffey AH, Flynn KF, GlendeninLE, Bentley WC, Essling AM (1971) Precision measurement of half-lives and specific acitivities of U and U. Phys Rev C4 1889 Kohman TP, Ames DP, Sedlet J (1949) The transuranium elements. National Nuclear Energy Series IV(14B) 1675... 

Sill CW, Williams RL. 1969. Radiochemical determination of uranium and the transuranium elements in process solutions and environmental samples. Anal Chem 41 1624-1632. 

Edwin M. McMillan (1951, chemistry discovery of the transuranium elements)... 

F. M. Rourke and R. P. Schuman Review of the Joint AECL-KAPL-Studies of the Transuranium Elements. Report KAPL-1781 (2. Juli 1957)-... 

The Transuranium Elements, Silliman Lectures, held at Yale University... 

Seaborg, The Transuranium Elements. Silliman Lectures, S. 80 ff. New Haven, Conn. Yale University Press Reading, Mass. Addison Wesley Publish. Co. 1958. 

Thompson, R.C. and Blair, W.J., The biological implications of the transuranium elements, Proceedings of the 11th Hanford Biology Symposium, Pergamon Press, London, 1972. 

The transuranium elements are also separated from each other by these means (115), (122), (136) and their order of elution from the columns, which, like the rare-earths, is a function of their atomic number, has been used as important evidence of the identity of the new elements (123). Separation from the rare-earths is not possible, however, as their elution peaks coincide with those of the actinides. This separation can be made, however, using hydrochloric acid as the elutriant. The actinides form anionic chloride complexes more readily than the rare-earths and are consequently more readily removed from the cationic resin (114). 

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