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# Melting points of giant covalent substances

Giant covalent substances are vast structures held together by many strong covalent bonds.

The melting of these compounds therefore involves the breaking of the numerous covalent bonds holding the atoms together.

More energy is required to break bonds in a covalent network than to separate covalent molecules. This accounts for the high melting and boiling points of giant covalent substances.

To melt quartz, all the covalent bonds must break.

Quartz melts at over $1600^{\circ}\text{C}$, while diamond melts at about $4000^{\circ}\text{C}$!