See also www.iupac.org/ See also www.iupac.org/ publications/ci/indexes/stamps.html publications/ci/indexes/stamps.html StampsStampsHed InternationalInternational , Where Art Thou?

n a press release dated 30 December 2015, the International Union of Pure and Applied Chemistry I(IUPAC) announced that a thorough review by independent experts of the experimental data avail- able for the syntheses of elements 113, 115, 117, and 118 has been concluded, and that the discovery of the four elements completing the 7th row of the was confirmed. The elemental names and sym- bols proposed shortly thereafter by the corresponding of Armenian descent and the scientifi c leader of the discovery teams met the criteria prescribed by IUPAC Flerov Laboratory of Nuclear Reactions at the Joint In- for naming new elements, and (Nh), mos- stitute for Nuclear Research in , , where covium (Mc), (Ts), and oganesson (Og), dozens of new superheavy have been made. became permanent within a few months. As such, the Interestingly, oganesson is only the second chemical ending of the name of element 118 and its location in element to be named after a living person since the the periodic table, below in 18, are con- name of element 106 (, Sg) was confi rmed sistent with the assumption that oganesson could be by IUPAC in 1997, when the legendary American chem- regarded as a noble . ist Glenn Seaborg (1912-1999) was still alive. The stamp also shows the -249 and -48 iso- However, the electronic structure of superheavy el- topes involved in the production of oganesson-294, ements, and consequently their physical and chemi- and the radioactive of Og-294 that cal properties, is signifi cantly aff ected by relativistic to the transient generation of -290, fl erovi- eff ects, even more so than the ones often invoked to um-286, and -282. explain the color of or the unexpectedly low melt- Now that we are quickly approaching the Interna- ing point of . In the case of oganesson, recent tional Year of the Periodic Table (2019), it is worth rec- calculations suggest that the element might be a liq- ognizing the eff ort of some of the scientists pursuing uid (or perhaps a ) near room temperature and the synthesis of new elements or the preparation of that OgF4 would be tetrahedral (unlike XeF4, which more stable isotopes of existing elements that would be is square planar). Experimental verifi cation of these amenable to chemical characterization. It is probably suggestions would be exceedingly diffi culty since only just a matter of time (and a considerable amount of re- a few of oganesson-294 have ever been gener- search) until elements 119 or 120 are added to the peri- ated, and they have a half-life of only 0.89 ms! odic table of the elements. Yuri, keep up the good work! The postage stamp illustrated in this note fea- tures Yuri T. Oganessian, a Russian nuclear physicist Written by Daniel Rabinovich

Mail a Stamp to Dan!

Prof. Daniel Rabinovich University of North Carolina at Charlotte Department of Chemistry Burson 200 9201 University City Boulevard Charlotte, NC 28223-0001 USA

Chemistry International October-December 2018 27