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Giant Molecules - the Structure of Graphite.
Whenever you come
across carbon, as a reactant or electrode,
carbon means graphite.
It can be written C(gr) but
is usually written as just C.
Graphite consists of many flat layers of hexagons (like chicken
wire).
The layers are called graphene sheets.
Each carbon atom is joined to
three other carbon atoms.
Each layer is itself a giant molecule with very
strong covalent
bonds.
Carbon is in group 4 of the periodic table and so it has four electrons in
its outer shell.
Three electrons are used for
bonding in the graphene sheet.
The fourth electron between the
layers is delocalised (it is a
free
electron).
Between the layers the
bonds are weak. Free electrons
between
the layers allows graphite to conduct electricity and heat.
The layers can easily
slide over each other making graphite
soft
and slippery and an
excellent lubricant (like oil).
See also carbon fibres, fullerenes and nanotubes.
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Copyright © 2008 Dr. Colin France. All Rights Reserved.
