Structures - (CCEA)Giant covalent structures

Ionic bonding holds ions together in a giant lattice. Covalent bonds create simple molecules or giant covalent structures. Different types of bonding give a substance different properties – different melting and boiling points, different electrical conductivity, and different solubility in water, among much else.

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Giant covalent structures

A is a three-dimensional structure of atoms that are joined by covalent bonds.

Allotropes are different forms of the same element, in the same state.

, and are allotropes of the same element (carbon) in the same state (solid). Carbon can form up to four covalent bonds.

Diamond

Diamond is a giant covalent structure in which each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral, three-dimensional structure. Diamond’s properties include:

  • high melting and boiling points. Diamond’s many covalent bonds are strong and substantial energy is needed to break them.
  • does not conduct electricity. Diamond has no free ions or electrons to move and carry the charge.
  • hardness. Diamond’s three-dimensional tetrahedral structure with strong covalent bonds makes it very hard.
Carbon atoms in a diamond
Figure caption,
The carbon atoms in a diamond form a regular tetrahedral structure.