Hi guys,
For a bond to be ionic, it requires that the constituent atoms have very different electronegativities. It would follow that the larger the difference, the greater the strength of the ionic bond; however, this doesn't seem to always be the case. For example, NaCl has a weaker ionic bond than MgS, even though the difference in electronegativites for Na and Cl is greater than that for Mg and S. I've read that MgS has a more powerful bond because it has a greater charge (+2/-2 as opposed to the +1/-1 for NaCl). I've also read that the charge is dependent on radii size (smaller atoms will have stronger bonds). So, clearly, in this example charge seems to trump electronegativity. Is this always the case? Or does greater electronegatvity ever trump differences in charge/radii size?
Thank you!