Why Bef2 has the lowest melting point
Answers
Answer:
Because you are assuming all ionic compounds are created equal when they are not. Bonds are rarely ever truly ionic and there is a long continuum from covalent bonds all the way to ionic bonds.
Be is a very strange element, it has only 4 electrons all of them are in S orbitals which means the atom is very small and has a very high charge density. You would think that favours ionic bonding but actually it favours covalent bonding. BeF2 is pretty much its most ionic compound but the Be-F distance is still very short, so the orbitals of each atom touch each other and that gives you a bond.
Be is a very odd beast, it is generally ignored when you are taught chemistry because it’s behaviour is hard to rationalise without going into far far too much detail for high school, at university level it is ignored because it is of very little interest to researchers, it is very expensive and toxic.
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