Which lattice type has a very high melting point and hardness due to covalent bonds throughout the structure?

Which lattice type has a very high melting point and hardness due to covalent bonds throughout the structure?

• A. Ionic lattice
• B. Simple covalent lattice
• C. Macro covalent lattice
• D. Metallic lattice

Answer: (C)

Giant covalent networks are held together by covalent bonds that extend throughout the entire crystal. Because every atom is bonded to many neighbors in a rigid three-dimensional network, to melt or deform the solid you must break a vast number of strong covalent bonds. That requires a lot of energy, giving very high melting points, and the network nature also makes the material extremely hard since there are no easy slip planes like in molecular solids. This kind of structure is described by a macro (giant) covalent lattice, which is why it fits best here. Ionic lattices and metallic lattices rely on different types of bonding, and a simple covalent lattice implies strong bonds within small units rather than an extended network across the whole solid.

Giant covalent networks are held together by covalent bonds that extend throughout the entire crystal. Because every atom is bonded to many neighbors in a rigid three-dimensional network, to melt or deform the solid you must break a vast number of strong covalent bonds. That requires a lot of energy, giving very high melting points, and the network nature also makes the material extremely hard since there are no easy slip planes like in molecular solids. This kind of structure is described by a macro (giant) covalent lattice, which is why it fits best here. Ionic lattices and metallic lattices rely on different types of bonding, and a simple covalent lattice implies strong bonds within small units rather than an extended network across the whole solid.