Question

When each tetrahedron is shares all of its oxygen atoms with four other tetrahedra in three-dimensional network, these crystalline structures are

Answer 1

Crystalline structures in which each silica tetrahedron shares its oxygen atoms with four other tetrahedra, forming a 3D network, are called covalent network crystals, exemplified by quartz, SiO₂.

Step-by-step explanation:

When each silica tetrahedron shares all of its oxygen atoms with four other tetrahedra, resulting in a three-dimensional network, these crystalline structures are known as covalent network crystals.

Covalent network crystals, such as quartz, consist of atoms covalently bonded to their nearest neighbor atoms at the lattice points of the crystal. Silica or silicon dioxide (SiO₂) is a prime example of this structure, characterized by strong silicon-oxygen bonds with each silicon atom being surrounded by four oxygen atoms in a tetrahedral configuration. These solids are notable for their hardness, high melting and boiling points, and inability to conduct electricity.