Allotropes of carbon, diamond , graphite and fullerene .
Compounds formed from carbon atoms of the element with different structures called carbon allotropes . Graphite , diamond , fullerene and amorphous carbon are examples of carbon allotropes known so far .In the table peridoik carbon element has the symbol C and atomic number 6 is in group 4A or 14 , and includes a block period of 2 p . Electron configuration is 1s2 2s2 carbon atom 2P2 or [ He ] 2s2 2P2 with the arrangement of electrons in the atomic shell is 2 , 4 . Based on electron configuration is known that carbon has 4 valence electrons . The four valence electrons of carbon can be used to form covalent bonds with other atoms or with other carbon atoms .
Diamond .
Some of the properties and the use of diamond ;
Diamond is the hardest natural mineral , so the diamond is widely used as a tool to cut , polish and a drill bit .
Has a very high melting point which is 4827 ° C) . This is due to the carbon - carbon covalent bonds are formed in the diamond structure is very strong even stronger than ionic bonds .
Form of heat insulator but can absorb very well . Electrical conductivity of diamonds relating to the electrons used to form bonds , where the electron - electron bonded diamond so strong that no electrons are free to move when given potential difference . Good heat absorbing properties of diamond applied to electronic equipment to absorb the heat generated when the electronic equipment used . With a diamond coating on the inner conductor temperature electronic equipment then the equipment will be maintained relatively constant so that the equipment can function normally .
Insoluble in water and organic solvents . In this case does not allow for the attraction between molecules of solvent and carbon atoms that can be unpacked attractions between carbon atoms that are covalently bonded . As a result of not being able solvation solvent molecules diamond .
In the structure of diamond each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral shape and the length of each carbon-carbon bond is 0.154 nm .
Diamonds can now scale commercial production in laboratory and industrial
scale . Namely the manufacture of diamond graphite with metal catalysts .
The process of making diamond from graphite performed at high temperatures of around 3500 ° C can be even higher and higher the pressure of around 140,000 atm or more . In addition to using the method , the diamond can be produced by the pyrolysis of hydrocarbons at relatively low temperatures ( ± 900 ° C ) and lower relative pressure of around 102 Pa. anyway .
In everyday life are often encountered diamond consists of a wide variety of colors .
Various diamond color produced is influenced by 3 things ;
The presence of impurities in the diamond structure so that the impurities can alter the absorption spectrum of diamond . Spectrum of diamond has changed due to impurities depending on the type and concentration of impurities existing instance of yellow and orange diamonds contain nitrogen , blue diamonds contain boron , diamond gray , purple and green hydrogen .
Green diamonds are caused by natural radiation , which occurs during the millions of years that can alter the atomic structure of the diamond . As a result of the changing structure of the diamond lead absorption sektrum diamonds changed .
Pink diamonds , red and brown caused by plastic deformation . The structure of carbon atoms that rotate during the formation of diamonds in the soil thus changing the absorption sektrum diamond . This is evident in the line of diamond veins that resemble wood grain . The line spectrum is what gives a different color .
Graphite .
In the structure of graphite each carbon atom to form a covalent bond with three other carbon atoms in a hexagonal arrangement to form a layered structure like a stack of cards . Because the carbon atom has four valence electrons on each carbon atom then there is still one that has not been bound electron (free electron).
Electrical conductivity properties owned by graphite influenced by electrons that are not used to form covalent bonds . These electrons are spread evenly on each C atom as overlap occurs as the bonding metal orbitals that form clouds or the sea of electrons . Therefore, when given potential difference , delocalised electrons will flow mostly toward the anode ( positive pole ) , the flow of electrons is what causes the electric current can flow . Meanwhile, when one end is heated then these electrons will immediately move towards the section that has a lower temperature . As a result, the heat will spread into the graphite which has a lower temperature .
Covalent bonding between the graphite layers are relatively weak when compared to the covalent bonds between atoms in a layer between . Given this causes the graphite is slippery, because the layer is at the top easily slips or easily displaced.
The nature and usefulness of Graphite .
Has a high melting point , the same as diamond . This is due to the covalent bond that is formed is so strong that the high energy required to decide .Has a soft nature , feels slippery and is used on a pencil after mixed clay .
Insoluble in water and organic solvents , because it is not capable of solvation molecules are very large graphite .
Compared to diamond , graphite has a density smaller , because of the structure are empty spaces between the pleats .
Conductor in the form of electricity and heat. Due to the nature of the graphite used as the anode of the battery ( cell Leclanche ) and as an electrode in electrolysis cells .
Fullerenes.
fullerenes structure
Fuleren are allotropes of carbon which one carbon molecule consisting of 60 carbon atoms that is often referred to as C60 . In the structure of fullerenes each carbon atom bonded to three other carbon atoms to form a pattern of arrangement of pentagonal form hollow structures such as a soccer ball .The nature and use .
Insoluble in water , but soluble in organic solvents .As a superconductor and a good heat sink . Superconducting properties and the heat absorbing electrons that are not related to one used to form covalent bonds , as in graphite . One of which is a C60 compound semiconductors are K3C60 .
So , thank you for reading this article. Written and posted by Bambang Sunarno.
sunarnobambang86@gmail.com
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name: Bambang Sunarno.
http://primadonablog.blogspot.com/2014/01/diamond-formation-process.html
DatePublished: January 24, 2014 at 13:38
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7MHPNPADAEFW.Tag ; Diamond formation process, fullerenes
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