Theoretical investigation of the XHgXeX and HHgXeX (XÂ =Â F, Cl, Br) compounds

► The linear noble gas compounds XHgXeX and HHgXeX (X = F, Cl, Br) were investigated at MP2 and CCSD(T) levels. ► FHgXeF, HHgXeF, HHgXeCl, HHgXeBr, and ClHgXeCl are higher in energy by 63.61, 70.87, 73.57, 71.91, and 70.37 kcal/mol, respectively, than the global minima. ► These five compounds are lower in energy by 25.35, 29.45, 12.49, 7.78, and 6.96 kcal/mol, respectively, than X(H)Hg + Xe + X. ► The reaction barrier of the five compounds through the bending transition state are 26.92, 15.74, 10.90, 10.45, and 20.27 kcal/mol, respectively.