something that is both ionic and covalent, for example nh4cl0

If it's ionic it has a very high boiling point. To my understanding, it is even higher than H-bonds.


NaCl boiling point:
1465 °C (1738 K)

As long as there are ionic bonds there, I would assume that the boiling point is going to be high.

something that is both ionic and covalent, for example nh4cl0
Although each component of this compound is held together with ionic bonds, but I think the compound overall is held together by ionic bonds, and anything that's held together by ionic bonds tends to have a relatively high bp.