Giant covalent compounds still use covalent bonds much like simple covalent molecules but they are made up of large structures of many atoms bonded together. The two most well known examples of these are Graphite and Diamond which are allotropes of Carbon. These structures have a lot of carbon atoms bonded to each other through strong covalent bonds.
The image above shows a part of a diamond structure. It has carbon atoms that are bonded to 4 other carbon atoms. As the carbon atoms have formed 4 strong covalent bonds, this means that diamond is very strong and hard. It also has a high melting and boiling point due to the large amounts of energy that are needed to break the bonds. Diamond also does not conduct electricity as it has no electrons that are free to move.
Graphite on the other hand has 3 covalent bonds between each of the carbon atoms and this means that there is a free electron. In the image below you can see the hexagonal structure of the graphite layers where each carbon is bonded to 3 more carbon atoms. A there is a free electron between the layers of graphite sheets electrons can move between these layers. This means that graphite can conduct electricity as these electrons are free to move. It also means that there are weak forces between these layers so graphite can be broken easily as it is brittle and the layers can slide over each other meaning it can be used as a lubricant.
Giant covalent structures is the term used to describe large non metallic strucutres that are made of many covalent bonds
A covalent bond forms when two or more atoms share a pair of electrons to form a bond
Graphite is a large covalent structure made of carbon with layers. Each carbon atom has 3 bonds between each.
Diamond is a large covalent structure of carbon with 4 bonds between each atom forming a large lattice structure
Allotropes are different forms of the same element just bonded in different structures. Carbon is a good example as it can be in the form of diamond and graphite with different structures and properties
Melting point is the temperature at which a solid turns into a liquid. The temperature when atoms have enough energy to over come their bonds and turn into a liquid.
Boiling point is the temperature at which a liquid turns into a gas. The particles have enough internal energy to overcome the bonds in the liquid.
Intermolecular forces are temporary interactions between ions, atoms or compounds that are not considered to be sharing electrons.
A lubricant is a substance that can be used to reduce friction between two surfaces
Conduct electricity is a property of substances when electrons and charged ions can move which means an electrical current can flow