CHEM HELP!!! why do most ionic compounds have such high melting and boiling points?

High melting and boiling points....

The properties that are often attributed to "ionic" bonding are actually a product of the type of structure. What often passes for "ionic" compounds are networks of atoms creating a lattice. The bonds between all of the atoms in the lattice, whether the bonds have high ionic character or high covalent character produce a structure which holds together at relatively high temperature.

Please undertand that in a network of atoms, one atom is not bonded to another single atom. Each atom is bonded to all of the adjacent atoms. For instance, in NaCl each Na atom is bonded to the six chlorine atoms which constitute it nearest neighbors, and that same Na atom is bonded to a second sphere of Cl atoms which is a but farther way, and the pattern repeats throughout the entire sample, so that to some degree each sodium atom is "bonded" to every chlorine atom.

Of the metal salts, you will find that it is primarily the alkali metals salts and alkaline earth metal salts which have the highest melting and boiling points. These have bonds with the highest ionic characters and the more polar bonds (greatest electronegativity differences). But across the transition metals the salts have much lower ionic character and lower melting and boiling points. For nonmetal - nonmetal network solids the bonds become even more covalent, but the melting and boiling points rise dramatically. Again, the higher melting points are due to the lattice structure, rather than the type of bonding.

The opposite ions in ionic compounds are held together by strong electrostatic forces. Therefore, a great amount of energy is needed to separate the opposite ions. This leads to high melting points of boiling points of ionic compounds.

strong intramolecular forces of attractions