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Allotropes of CarbonAllotropes of Carbon
DiamondGraphite“Buckyballs” or buckminsterfullerene
DiamondGraphite“Buckyballs” or buckminsterfullerene
Allotrope definitionAllotrope definition
Different structural/crystalline forms of the same element
Different structural/crystalline forms of the same element
DiamondDiamond
Each carbon atom is bonded to 4 others to form a giant covalent network or lattice
Each carbon atom is bonded to 4 others to form a giant covalent network or lattice
DiamondDiamond
Each carbon atom is bonded to 4 others to form a giant covalent network or lattice
Is bond is of the same length and equally strong so the carbon atoms are sp3 hybridized
Each carbon atom is bonded to 4 others to form a giant covalent network or lattice
Is bond is of the same length and equally strong so the carbon atoms are sp3 hybridized
DiamondDiamond
Each carbon atom is bonded to 4 others to form a giant covalent network or lattice
Is bond is of the same length and equally strong so the carbon atoms are sp3 hybridized
As all the electrons are localised (fixed in position), diamond is exceptionally hard and it does not conduct electricity
Each carbon atom is bonded to 4 others to form a giant covalent network or lattice
Is bond is of the same length and equally strong so the carbon atoms are sp3 hybridized
As all the electrons are localised (fixed in position), diamond is exceptionally hard and it does not conduct electricity
DiamondDiamond
From: ibchem.com/IB/ibnotes/full/bon_htm/14.4.htm
Properties of DiamondProperties of Diamond
Very high melting point
Doesn’t conduct electricity
Very hard
Very high melting point
Doesn’t conduct electricity
Very hard
GraphiteGraphite
Each carbon atom is bonded to 3 other carbon atoms to give layers of hexagonal rings
Each carbon atom is bonded to 3 other carbon atoms to give layers of hexagonal rings
GraphiteGraphite
Each carbon atom is bonded to 3 other carbon atoms to give layers of hexagonal rings
As each bond is the same, the carbon atoms are sp2 hybridised
Each carbon atom is bonded to 3 other carbon atoms to give layers of hexagonal rings
As each bond is the same, the carbon atoms are sp2 hybridised
GraphiteGraphite
Each carbon atom is bonded to 3 other carbon atoms to give layers of hexagonal rings
As each bond is the same, the carbon atoms are sp2 hybridised
The remaining p orbital electron is delocalised to form weak bonds between the layers
Each carbon atom is bonded to 3 other carbon atoms to give layers of hexagonal rings
As each bond is the same, the carbon atoms are sp2 hybridised
The remaining p orbital electron is delocalised to form weak bonds between the layers
GraphiteGraphite
Each carbon atom is bonded to 3 other carbon atoms to give layers of hexagonal rings
As each bond is the same, the carbon atoms are sp2 hybridised
The remaining p orbital electron is delocalised to form weak bonds between the layers
The covalent layer lattice has all sigma bonds
Each carbon atom is bonded to 3 other carbon atoms to give layers of hexagonal rings
As each bond is the same, the carbon atoms are sp2 hybridised
The remaining p orbital electron is delocalised to form weak bonds between the layers
The covalent layer lattice has all sigma bonds
GraphiteGraphite
From: http://physics.bu.edu/cc104/covalent.html From: http://physics.bu.edu/cc104/covalent.html
GraphiteGraphite
Because of the layers, graphite is an excellent lubricant as the layers can slide over each other
Because of the layers, graphite is an excellent lubricant as the layers can slide over each other
GraphiteGraphite
Because of the layers, graphite is an excellent lubricant as the layers can slide over each other
Graphite is also a good conductor of electricity because of the delocalised electrons e.g. carbon rods, lead pencils
Because of the layers, graphite is an excellent lubricant as the layers can slide over each other
Graphite is also a good conductor of electricity because of the delocalised electrons e.g. carbon rods, lead pencils
BuckminsterfullereneBuckminsterfullerene
Is one member of a family of spherical carbon molecules sometimes called “buckyballs”
Has the formula C60
The C atoms are arranged in hexagons and pentagons to give a geodesic spherical structure similar to a football
Is one member of a family of spherical carbon molecules sometimes called “buckyballs”
Has the formula C60
The C atoms are arranged in hexagons and pentagons to give a geodesic spherical structure similar to a football
BuckminsterfullereneBuckminsterfullerene
From: www.vega.org.uk/video/programme/65
Vancouver GeodesicVancouver Geodesic
From: http://www.flickr.com/photos/sharply_done/416104996/
BuckminsterfullereneBuckminsterfullerene
Like in graphite, each carbon atom is bonded to 3 others
Like in graphite, each carbon atom is bonded to 3 others
BuckminsterfullereneBuckminsterfullerene
Like in graphite, each carbon atom is bonded to 3 others
Each carbon atom is sp2 hybridized
Like in graphite, each carbon atom is bonded to 3 others
Each carbon atom is sp2 hybridized
BuckminsterfullereneBuckminsterfullerene
Like in graphite, each carbon atom is bonded to 3 others
Each carbon atom is sp2 hybridized
There are also delocalized electrons, hence C60 can conduct electricity slightly
Like in graphite, each carbon atom is bonded to 3 others
Each carbon atom is sp2 hybridized
There are also delocalized electrons, hence C60 can conduct electricity slightly
From: www.nanomaterialsdiscovery.com/technology.php...
Silicon Silicon dioxide - SiO2
From: http://www.galleries.com/minerals/elements/silicon/silicon.htm , www.fiji.hotel-pictures.com/.../beach2.html
Silicon Silicon dioxide - SiO2
From: http://www.galleries.com/minerals/elements/silicon/silicon.htm , www.fiji.hotel-pictures.com/.../beach2.html
Structure of SiliconStructure of Silicon
Silicon contains 4 valence electrons
It forms a lattice similar to that of diamond - each Si atom bonded to 4 others
Silicon is fairly unreactive and acts as an insulator at low temperatures as it has no free electrons
With impurities added it can conduct electricity at low temperatures
Silicon contains 4 valence electrons
It forms a lattice similar to that of diamond - each Si atom bonded to 4 others
Silicon is fairly unreactive and acts as an insulator at low temperatures as it has no free electrons
With impurities added it can conduct electricity at low temperatures
From: http://web1.caryacademy.org/chemistry/rushin/StudentProjects/ElementWebSites/silicon/Structure.htm
Structure of silicon dioxideStructure of silicon dioxide
Commonly known as silica and seen as sand or quartz
Like diamond, SiO2 is also a giant covalent lattice/ structure
Each Si atom is bonded to 4 O atoms, and each O atom is bonded to 2 Si atoms
Commonly known as silica and seen as sand or quartz
Like diamond, SiO2 is also a giant covalent lattice/ structure
Each Si atom is bonded to 4 O atoms, and each O atom is bonded to 2 Si atoms
From: http://www.moe.gov.sg/edumall/tl/digital_resources/chemistry6.htm , http://electronics.howstuffworks.com/quartz-watch2.htm
Properties of silicon dioxide
Properties of silicon dioxide
has a high melting point - varying depending on what the particular structure is (remember that the structure given is only one of three possible structures), but around 1700°C. Very strong silicon-oxygen covalent bonds have to be broken throughout the structure before melting occurs.
is hard. This is due to the need to break the very strong covalent bonds.
doesn't conduct electricity. There aren't any delocalised electrons. All the electrons are held tightly between the atoms, and aren't free to move
is insoluble in water and organic solvents. There are no possible attractions which could occur between solvent molecules and the silicon or oxygen atoms which could overcome the covalent bonds in the giant structure.
has a high melting point - varying depending on what the particular structure is (remember that the structure given is only one of three possible structures), but around 1700°C. Very strong silicon-oxygen covalent bonds have to be broken throughout the structure before melting occurs.
is hard. This is due to the need to break the very strong covalent bonds.
doesn't conduct electricity. There aren't any delocalised electrons. All the electrons are held tightly between the atoms, and aren't free to move
is insoluble in water and organic solvents. There are no possible attractions which could occur between solvent molecules and the silicon or oxygen atoms which could overcome the covalent bonds in the giant structure.
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