Allotropes of carbon Flashcards
what are allotropes
different structural forms of the same element in the same physical state.
why is diamond hard
giant covalent structure, made up of carbon atoms that each form four covalent bonds. this makes it very hard
why do diamonds not conduct electricity
no free electrons or ions.
what is graphites structure
each carbon atom only forms 3 covalent bonds, creating sheets of carbon atoms arranged in hexagons.
what are the covalent bonds like in graphite
there aren’t any covalent bonds between the layers - they are only held together weakly, so they are free to move over each other.
This makes graphite soft and slippery, so its ideal as a lubricating material
why does graphite have a high melting point
the covalent bonds in the layers need loads of energy to break
how does graphite conduct electricity and thermal energy
only three out of each carbons four outer electrons are used in bonds, so each carbon atom has one electron thats free and can move
what is graphene
sheet of carbon atoms joined together in hexagons
sheet is just one atom thick, making it a two-dimensional substance.
what is the network of covalent bonds like in graphene
network of covalent bonds makes it very strong. also incredibly light, so can be added to composite materials to improve their strength without adding much weight
how can graphene conduct electricity
contains delocalised electrons so it can conduct electricity through the whole structure. can be used in electronics
what are fullerenes
molecules of carbon, shaped like closed tubes or hollow balls
what are fullerenes made up of
carbon atoms arranged in hexagons but can also contain pentagons
what can fullerene be used for
to ‘çage’ other molecules.
structure of fullerene
forms around another atom or molecule, which is then trapped inside
how much surface area do fullerenes have
huge surface area - so they can make great industrial catalysts
