[pokepoke]

It is given that silicon oxide is a giant molecular structure which would require very large amount of energy to overcome the extensive covalent bonding.

I always though that the melting point of giant molecular > giant ionic (usually).

But how come its melting point is lower than Magnesium oxide and Aluminium oxide which are giant ionic structure.

What are the reasons for this result? Is there something got to do with covalent characteristic in ionic bond?