On the stability and chemical bond of noble gas halide cations NgX⁺ (Ng = He – Rn; X = F – I)

Abstract

Despite the belief that noble gases (Ng) are completely inert and cannot form stable molecules, a variety of Ng compounds have been reported under laboratory conditions and others were recently detected in the interstellar media, raising interest in knowing and studying their bond nature and the physicochemical properties associated with their stability. In the present work, a systematic analysis of the thermodynamic stability of noble gas halide cations (NgX +) at the CCSD(T)/def2-QZVP level have been performed. In addition, chemical bond was characterized through Natural Bonding Theory (NBO), Quantum Theory of Atoms in Molecules (QTAIM) and Energy Decomposition Analysis (EDA) with relativistic corrections. All methods suggest that NgX + compounds possess a strong covalent bond. However, results show that only compounds containing Ar-Rn atoms are thermodynamic stable with a highly energetic and endergonic dissociation process. For these reasons, it is possible to suggest that several compounds that have not yet been reported could be obtained at the laboratory level or observed in the interstellar medium.

Bonding Nature between Noble Gases and Small Gold Clusters

“…In addition, the Au–Ng bonding is characterized with Wiberg ( W ) indexes (Table ), calculated between Au and the atop- and bridge-coordinated Ng atoms in Au 3 Ng 6 + . Typically, bonds with W indexes exceeding 0.5 are characterized as covalent . For the atop-coordinated Ng atoms, W values are high, all above 0.5, in agreement with bonds having significant covalent character.…”

Exploring the Nature of Chemical Bonding between Noble Gases and Hypercoordinate Group 13 Compounds: Beyond Boron

“…The chemical bond of those molecules has been systematically studied, even with the possibility of the formation of C–He and C–Ne bonds at very low temperatures. Additionally, it is known that heavier gases form hypercoordinated compounds with fluorine. , On the other hand, the chemical bonding of noble gases with other atoms is not only limited to elements of period 2 of the periodic table but also the bonding capacity with silicon, sulfur, chlorine, among others − has been explored. However, the ability of noble gases to bond hypercoordinated containing heavier group 13 elements has not been systematically studied.…”

Strong carbon – noble gas covalent bond and fluxionality in hypercoordinate compounds

“…In recent years, several investigations have been carried out that state, from both the theoretical and experimental point of view, that the group 18 elements, also known as noble gases, can form chemical bonds with other elements. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Although this goes beyond the conventional wisdom that group 18 elements are inert, it has been proposed that they can form strong bonds with electron-deficient atoms or groups. 2 One of the cases that have attracted the most attention is the formation of B-Ng bonds, where the latter donates electrons to the empty p-orbital of B, thus forming a s-covalent bond.…”