Superheavy Element Flerovium (Element 114) Is a Volatile Metal

Abstract

Superheavy Element Flerovium (Element 114) Is a Volatile MetalAccess to the published version may require subscription. Superheavy Element Flerovium (Element 114) is a Volatile MetalAlexander Yakushev †, , Jacklyn M. ABSTRACT: The electron shell structure of superheavy elements, i.e., elements with atomic number Z ≥ 104, is influenced by strong relativistic effects caused by the high Z. Early atomic calculations on element 112 (copernicium, Cn) and element 114 (flerovium, Fl) having closed and quasiclosed electron shell configurations of 6d 10 7s 2 and 6d 10 7s 2 7p 1/2 , respectively, predicted them to be noble gas-like due to very strong relativistic effects on the 7s and 7p 1/2 valence orbitals. Recent fully relativistic calculations studying Cn and Fl in different environments suggest them to be less reactive compared to their lighter homologs in the groups, but still exhibiting a metallic character. Experimental gassolid chromatography studies on Cn have, indeed, revealed a metal-metal bond formation with Au. In contrast to this, for Fl, the formation of a weak bond upon physisorption on a Au surface was inferred from first experiments. Here, we report on a gas-solid chromatography study of the adsorption of Fl on a Au surface. Fl was produced in the nuclear fusion reaction 244 Pu( 48 Ca, 3-4n) 288,289 Fl and was isolated in-flight from the primary 48 Ca beam in a physical recoil separator. The adsorption behavior of Fl, its nuclear α-decay product Cn, their lighter homologs in groups 14 and 12, i.e., Pb and Hg, and the noble gas Rn were studied simultaneously by isothermal gas chromatography and thermochromatography. Two Fl atoms were detected. They adsorbed on a Au surface at room temperature in the first, isothermal part, but not as readily as Pb and Hg. The observed adsorption behavior of Fl points to a higher inertness compared to its nearest homolog in the group, Pb. However, the measured lower limit for the adsorption enthalpy of Fl on a Au surface points to the formation of a metal-metal bond of Fl with Au. Fl is the least reactive element in the group, but still a metal.

Chemistry of the superheavy elements

“…In recent years, the first successful chemistry experiments were performed with Cn [28][29][30] and Fl [31,32]. Hot fusion reactions with targets of 242 Pu and 244 Pu and beams of 48 Ca provided access to 0.5-s 287 Fl, 0.69-s 288 Fl and 2.1-s 289 Fl.…”

“…Ground-breaking experiments on the formation, stability, volatility and detection of Sg(CO) 6 were performed with the cryo-thermochromatograhy detector COMPACT [32] coupled to the GARIS recoil separator of RIKEN [68] where pre-separated 265 Sg is available at a rate of about oneatom-per-hour for chemical investigations [63]. This experiment demonstrated atom-at-a-time the formation (even at a low CO pressure), separation and detection of Sg(CO) 6 [69].…”

“…(A similar technique has been used earlier for lighter SHEs in high-temperature TC [11].) This allowed a fast and efficient transport of chemically pre-separated HsO 4 to (iii) newly developed c-TC detectors known as COLD [44], CTS [71] and COMPACT [32]. In the first experiment, seven nuclear decays of Hs isotopes were observed [44].…”

Laser spectroscopy studies on nobelium

“…Copernicium was actually found to be a rather regular member of group twelve [9], while the properties of flerovium are still a matter of ongoing research [10,11].…”

Prediction of the thermal release of transactinide elements (112 ≤Z≤ 116) from metals

“…First thermochromatographic investigations of E108 (Hs), Cn, and Fl have been performed using the Cryo On-Line Detector array [6][7][8][9]. For nuclear decay studies of several Hs isotopes the more efficient COMPACT [10,11] was developed, which was later on also adapted for SHE adsorption studies on gold surfaces. All these methods have in common that the connection between the production of transactinide atoms in heavy ion induced nuclear fusion reactions and the setups dedicated to their chemical investigation is a stopping gas volume flushed by a carrier gas.…”