Determination of molecular properties for moscovium halides (McF and McCl)

Advanced relativistic quantum chemistry calculations were used for the first time to provide accurate determinations of fundamental molecular properties for two moscovium halides (McX, X = F and Cl). The recommended values presented here were obtained with the X2C-MMF-CCSD-T/RPF-4Z level of theory. Thus, we determined an equilibrium bond length (re) of 2.287 A, an equilibrium dipole moment (μe) of 6.59 D and a harmonic vibrational frequency (ωe) of 405 cm−1 for McF. On the other hand, the results for McCl show re, μe and ωe values equal to 2.728 A, 7.46 D and 244 cm−1, respectively. The same Mc+–X− polarity is predicted in molecules of both halides. The equilibrium dissociation energies attained in X2C-MMF-(FS)CCSD/RPF-4Z calculations are 4.04 and 3.45 eV for McF and McCl, respectively. Therefore, the Mc–F and Mc–Cl bonds are predicted to be slightly stronger than Bi–F and Bi–Cl ones, respectively. Finally, the huge values obtained for dipole moments in the molecules studied strongly suggest that moscovium halides are predominantly ionic compounds.