The temperature variation of the fractionation of oxygen in exchange reactions between dissolved carbonate and water and between calcite and water and calculated on theoretical grounds, and checked experimentally. In the course of the experiments it was necessary to investigate several methods of decomposing calcium carbonate to carbon dioxide for mass spectrometer analysis. A method was developed for growing calcium carbonate from solution with the same isotopic composition as the carbonate shells of organisms produced at the same temperature from water of the same isotopic composition, and the results of these experiments at various temperatures are expressed in an equation relating the temperature of formation with the isotopic composition of the calcium carbonate and of the water.

On the Isotopic Chemistry of Carbonates and a Paleotemperature Scale

羟氨苄青霉素引起大疱性类天疱疮样疹

Uranium solution-mineral equilibria at low temperatures with applications to sedimentary ore deposits

A table is presented of a complete list of the radioactive and stable isotopes, with a number of their salient features, as recorded in the literature or by private communications up to February 1958. (W.D.M.)

Table of isotopes

Electronegativity values from thermochemical data

One.- 8. Americium.- 9. Curium.- 10. Berkelium.- 11. Californium.- 12. Einsteinium.- 13. Transeinsteinium Elements.- Two.- 14. Summary and comparative aspects of the actinide elements.- 15. Spectra and electronic structures of free actinide atoms and ions.- 16. Optical spectra and electronic structure of actinide ions in compounds and in solution.- 17. Thermodynamic properties.- 18. Magnetic properties.- 19. The metallic state.- 20. Structural chemistry.- 21. Solution chemistry and kinetics of ionic reactions.- 22. Organoactinide chemistry: properties of compounds having metal-carbon bonds only to ?-bonded ligands.- 23. Organoactinide chemistry: properties of compounds with actinide-carbon, actinide-transition-metal ? bonds.- 24. Future elements (including superheavy elements).- Appendix I.- Nuclear spins and moments of the actinides.- Appendix II.- Nuclear properties of actinide nuclides.- Author Index (Volumes 1 and 2).- Subject Index (Volumes 1 and 2).

The chemistry of the actinide elements

The place of the very heaviest elements in the periodic system is of great scientific interest and is of crucial importance in understanding the physical and chemical properties of these elements. Ideas on this question have varied considerably over the years. Periodic charts have commonly placed thorium, protactinium, and uranium in positions immediately below the elements hafnium, tantalum, and tungsten. The latter group of elements are members of a transition series in which the 5d electron shell is being filled. Hence this earlier placement of the three heavy elements corresponded to the assumption that they are members of a 6d transition series. Indeed thorium, protactinium, and, to a much smaller extent, uranium do show considerable resemblance in chemical properties to the 4d and 5d transition series elements. The electronic configuration beyond the radon core on this basis would be written thus: thorium (6d 27s 2), protactinium (6d 37s 2), and uranium (6d 47s 2).

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Glenn T. Seaborg

Papers

Table of isotopes

The chemistry of the actinide elements

The transuranium elements

The nuclear properties of the heavy elements

The actinide elements