4. In general, EDMBs occur at smaller pressures along the series Se-Te-Po and As-Sb-Bi. This means that the effect of pressure is equivalent to the substitution of the composition of elements by their heavy analogs. This result is consistent with the larger distortion of octahedral coordination for the lighter elements, i.e. those with stronger LEP stereoactivity. It is also consistent with the well-known effect that pressure is equivalent to going down the group in the periodic table since pressure induces a decrease of the LEP stereoactivity in the same way as going down the group to heavier elements. Therefore, both pressure and composition tend to transform covalent ppσ-bonds into EDMBs and finally into metallic bonds. Interestingly, both pressure and composition lead to an increase in mass density, which in turn results in an increase in electronic density. Therefore, other ways of increasing electronic density could also lead to a decrease in the LEP stereoactivity and the formation of EDMBs. Two examples are chemical pressure and reduction, i.e. providing electrons to the system .