Reactivity of the Superheavy Element 115, Mc, and Its Lighter Homologue, Bi, with Respect to Gold and Hydroxylated Quartz Surfaces from Periodic Relativistic DFT Calculations: A Comparison with Element 113, Nh

Abstract

Adsorption energies (E ads) of the superheavy element (SHE) Mc, its lighter homologue (Bi), as well as of another superheavy element Nh and some lighter homologues of SHEs on gold and hydroxylated quartz surfaces are predicted via periodic relativistic density functional theory calculations. The aim of this study is to support “one-atom-at-a-time” gas-phase chromatography experiments that are examining the reactivity and volatility of Mc. The obtained E ads values of the Bi and Mc atoms on the Au(111) surface are >200 kJ/mol. On the hydroxylated quartz surface, Mc should adsorb with a minimal energy of 58 kJ/mol. On both types of surfaces, E ads(Mc) should be ∼100 kJ/mol smaller than E ads(Bi) due to strong relativistic effects on its valence 7p electrons. A comparison with other SHEs under investigation shows that Mc should adsorb on gold more strongly than Cn, Nh, and Fl, while on quartz, Mc should adsorb like Nh, with both of them absorbing more strongly than volatile Cn and Fl. The highest reactivity of Mc in the row of the 7p elements is caused by the largest orbital and relativistic destabilization and expansion of the 7p3/2 atomic orbital. Using the calculated E ads, the distribution of the Nh and Mc events in the gas-phase chromatography column with quartz and gold-plated detectors is predicted via Monte Carlo simulations. As a result, Mc atoms should be almost 100% adsorbed in the first section of the chromatography column on quartz, while a few atoms of Nh can reach the second part of the column with gold-plated detectors.

Reactivity of superheavy elements Cn and Fl and of their oxides in comparison with homologous species of Hg and Pb, respectively, towards gold and hydroxylated quartz surfaces

“…23,24 Periodic calculations via the VASP computational package based on the projector-aug-mented plane-wave (PAW) method and pseudopotentials 25 also appeared, with results being overall in good agreement with ours. [20][21][22] The results of all those calculations have shown that Cn should be more volatile than Hg over gold, which is a relativistic effect, however, still forming the Cn-Au chemical bond. 21,22 For Fl, the calculations have shown that it should interact with gold more strongly than Cn, but much more weakly than Pb, which is also a relativistic effect 21,22,25 (see the values in the summary table below).…”

“…[20][21][22] The results of all those calculations have shown that Cn should be more volatile than Hg over gold, which is a relativistic effect, however, still forming the Cn-Au chemical bond. 21,22 For Fl, the calculations have shown that it should interact with gold more strongly than Cn, but much more weakly than Pb, which is also a relativistic effect 21,22,25 (see the values in the summary table below).…”

“…We started with a cluster approach and 4-component density functional theory, 4c-DFT, calculations, 19 followed by periodic calculations based on a zeroth-order regular approximation (ZORA) with two components, 2c-ZORA, using the ADF BAND suite. [20][21][22] Works of other researchers via the 2c-DFT cluster approach followed. 23,24 Periodic calculations via the VASP computational package based on the projector-aug-mented plane-wave (PAW) method and pseudopotentials 25 also appeared, with results being overall in good agreement with ours.…”

First Study on Nihonium (Nh, Element 113) Chemistry at TASCA

“…Thus, the reactivity of both Mc and Nh has to be taken into account. Nihonium and moscovium are predicted to be less reactive than their nearest homologues Tl and Bi, respectively ( Pershina et al, 2009 ; Fox-Beyer and van Wüllen, 2012 ; Rusakov et al, 2013 ; Pershina, 2016 ; Pershina and Iliaš, 2019 ; Trombach et al, 2019 ; Pershina et al, 2021 ). The calculated first ionization potential ( IP ) of Nh (7.306 eV) ( Eliav et al, 1996 ) is larger than that of Tl (6.11 eV).…”

“…The unpaired p 1/ 2 -electron may cause increased chemical reactivity, while the spherical 7p 1/2 orbital is relativistically stabilized. Accordingly, Nh is predicted to be more reactive upon adsorption on gold and quartz surfaces than its neighbors Cn and Fl, but less reactive than Tl, its nearest homologue in group 13 ( Pershina et al, 2009 ; Fox-Beyer and van Wüllen, 2012 ; Rusakov et al, 2013 ; Pershina, 2016 ; Pershina et al, 2021 ). The large spin-orbit splitting in the 7p shell is reflected in its chemical behaviour - Nh appears to be more inert than lighter homologues in the group 13, but can form stable compounds, such as hydrides or hydroxide NhOH.…”