This essay investigate's different chemical structures and how they are formed.

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Structures are crucial for everyday life and, this essay investigated different chemical structures and how they are formed.

Giant Covalent Structures

In this section I wish to investigate on giant covalent structures, and I will focus mainly on the structures of ddiamond, graphite.

The structure of diamond: The giant covalent structure of diamond

Carbon has an electronic arrangement of 2, 4. In diamond, each carbon shares electrons with four other carbon atoms - forming four single bonds.

In the diagram some carbon atoms only seem to be forming two bonds, but that's not really the case. I am only showing a small bit of the whole structure. This is a giant covalent structure - it continues on and on in three dimensions. It is not a molecule, because the number of atoms joined up in a real diamond is completely variable - depending on the size of the crystal.

The physical properties of diamond


* Has a very high melting point (almost 4000°C). Very strong carbon-carbon covalent bonds have to be broken throughout the structure before melting occurs.

* Is very hard. This is again due to the need to break very strong covalent bonds operating in 3-dimensions.

* Doesn't conduct electricity. All the electrons are held tightly between the atoms, and aren't free to move.

It is insoluble in water. There are no possible attractions which could occur between solvent molecules and carbon atoms which could outweigh the attractions between the covalently bound carbon atoms.

The structure of graphite: The giant covalent structure of graphite
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Graphite has a layer structure which is quite difficult to draw convincingly in three dimensions. The diagram below shows the arrangement of the atoms in each layer, and the way the layers are spaced:

The bonding in graphite

Each carbon atom uses three of its electrons to form simple bonds to its three close neighbors. That leaves a fourth electron in the bonding level. These "spare" electrons in each carbon atom become delocalized over the whole of the sheet of atoms in one layer. They are no longer associated directly with any particular atom or pair ...

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