Chemistry of the Heaviest Elements- One Atom at a Time

Abstract

FutureMore "In-Depth" Chemical Studies Chemistry beyond Seaborgium? 93 NpIn keeping with the goal of the Viewpoints series of the Journal of Chemical Education, this article gives a 75-year perspective of the chemistry of the heaviest elements, including a 50-year retrospective view of past developments, a summary of current research achievements and applications, and some predictions about exciting, new developments that might be envisioned within the next 25 years. A historical perspective of the importance of chemical separations in the discoveries of the transuranium elements from neptunium (Z = 93) through mendelevium (Z = 101) is given. The development of techniques for studying the chemical properties of mendelevium and still heavier elements on the basis of measuring the radioactive decay of a single atom ("atom-at-a-time" chemistry) and combining the results of many separate experiments is reviewed. The influence of relativistic effects (expected to increase as Z 2 ) on chemical properties is discussed. The results from recent atom-at-a-time studies of the chemistry of the heaviest elements through seaborgium (Z = 106) are summarized and show that their properties cannot be readily predicted based on simple extrapolation from the properties of their lighter homologues in the periodic table. The prospects for extending chemical studies to still heavier elements than seaborgium are considered and appear promising.

First Ionization Potentials of Fm, Md, No, and Lr: Verification of Filling-Up of 5f Electrons and Confirmation of the Actinide Series

“…3 However, much less is known about the heavier actinides due to stringent limitation on experimental procedures 4 with increasing atomic number as these heavy elements are available in decreasing quantities of only one atom at a time. 5,6 The first ionization potential (IP 1 ) of an atom is one of the most fundamental chemical and physical quantities of every element. The first measurements of IP 1 of actinides were performed by a surface ionization technique.…”

An ultra-incompressible ternary transition metal carbide

“…27,28 Though tungsten and molybdenum have exceedingly similar atomic radii, tungsten has a greater d electron orbital compared with molybdenum which increases the overlap of the electron. 29 It is just this greater overlap that results in a strong W-C bond. Considering this material has the same crystal structure, adding the stronger W-C bonds will resist the collapse when an external force is applied to the sample surface.…”

La tabla periódica en el Journal of chemical education a través del siglo XX.

“…Dentro de los artículos revisados, sólo Menschutkin (1937) define explícitamente elemento, aunque otros discutan tangencialmente las definiciones históricas. No obstante, a pesar de no estar explícita, esta polisemia del concepto elemento sí se trasluce en el Journal of Chemical Education (JCE) en la variedad de tablas encontradas basadas en aspectos tan diferentes como el estado de agregación (Ternsrom, 1964;Marshall, 2000), las estabilidades nucleares o la desintegración de elementos radioactivos (King y Fall, 1940) o la química de "un solo átomo" (Hoffman y Lee, 1999). Los libros de texto reflejan esta misma pluralidad (Roundy, 1989;Thibault et al, 1994;Bullejos et al, 1995).…”