Stable copernicium hexafluoride (CnF6) with an oxidation state of VI.

As the heaviest group 12 element known currently, copernicium (Cn) often presents the oxidation states of I+, II+, and rarely IV+ as in its homologue mercury. In this work we systematically studied the stability of some oxides, fluorides, and oxyfluorides of Cn by two-component relativistic calculations and found that the CnF6 molecule with an oxidation state of VI+ has an extraordinary stability. CnF6 may decompose into CnF4 by conquering an energy barrier of about 34 kcal mol-1 without markedly releasing heat. Our results indicate that CnF6 may exist under some special conditions.