Allotropes of Carbon and Silicon

Buckminster fullerene (C60)

• Spherical shape made up of a cage like ring structure (truncated icoshedron)

• Resembles a soccer ball with 20 hexagons, 12 pentagons, a carbon atom at each vertex of each polygon and a bond along each polygon edge.

• Most common naturally occurring fullerene molecule

• Often found in soot

Carbon Nanotubes

• allotropes of carbon with a cylindrical nanostructures

• Nanotubes form a small portion of the materials in some (primarily carbon fiber) baseball bats, golf clubs, car parts or damascus steel

• Nanotube structures are hollow with walls formed by one-atom-thick sheets of carbon, called graphene.

• These sheets are rolled at specific and distinct ("chiral") angles, and the combination of these rolling angles and radii depict the nanotubes properties

• Nanotubes can either be single-walled nanotubes (SWNTs) or multi-walled nanotubes (MWNTs)

• The chemical bonding of nanotubes is composed entirely of sp2 bonds, similar to those of graphite

• These bonds are stronger than the sp3 bonds found in alkanes and diamond, and they provide nanotubes with their unique strength.

Structure of Diamond

3D diagram of Diamond:

• Each Carbon atom is covalently bonded to four other Carbons in a tetrahedron.
• These tetrahedrons come from a 3 dimensional network of 6- member carbon rings
• This causes them to have a bond angle of 109.5 degrees
• This stable network of covalent bonds and hexagonal rings is why diamond is so strong

Physical Properties

Silicon Dioxide (SiO2)

Allotropes of Carbon: Fullerene

Diamond Related back to Bonding

• All elements are carbon, so it is non polar
• Diamond has no Lone Pair Electrons
• It is a tetrahedral so its angle is 109.5 degrees
• Diamond is very stable
• Melting point is very high because of the stability of the element

Two of the more popular shapes of fullerene are nanotubes and buckminsterfullerene (bucky balls).

Fun facts:

• Solid and gaseous forms of fullerene have been found in deep space

• April 2003, fullerenes were under study for potential medicinal use: binding specific antibiotics to the structure to target resistant bacteria and even target certain cancer cells such as melanoma (skin cancer)

• Owing to the material's exceptional strength and stiffness, nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1, which is significantly larger than for any other material.

• 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.

Diamond:

• Diamond is one of the 4 allotropes of the Carbon element.
• It is valued for it's hardness and heat conductivity
• No known substance can cut (or even scratch) a diamond, except another diamond.

Physical Properties of Diamond

is hard. This is due to the need to break the very strong covalent bonds.

• Hardest substance in Earth's existence
• Solid
• Colors range from white to blue to pink (usually clear).
• Not malleable
• Not ductile
• Very Brittle

• doesn't conduct electricity. There aren't any delo
• calised electrons. All the electrons are held tightly between the atoms, and aren't free to move.

Chemical Properties of Diamond

C60 Fullerene (Buckminsterfullerene)

• Chemical stability= not very reactive, even strong to acids and bases
• It is very stable and does not react very easily
• Surface can be oxidized by a few oxidants at a high temperature.
• Diamond is a very good Heat conductor

Graphene

• 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.

Graphite

Carbon Nanotube

Graphene Fun Facts

• Crystalline allotrope of Carbon with 2-dimensional properties
• A single atomic layer of graphite
• Very tightly bonded carbon atoms organized in a hexagonal lattice
• First isolated in 2004 in the University of Manchester by Prof Andre Geim and Prof Kostya Novoselov

VSEPR

Trigonal Planar with 1 leftover electron in the third dimension used to conduct electricity and heat. Each C atom has an angle of 120°

• a single-layer sheet of graphene the size of a football field would weigh less than a gram!
• The first 2-D substance isolated
• It has the highest ratio of edge atoms of any carbon allotrope
• It has a very thin atomic thickness at 0.345 Nm

Facts on Graphite

Van der Waals forces:

Attractive or repulsive forces between molecules or atomic groups that do not arise from a covalent bond, or ionic bonds

-Weak non-bonding interaction between layers results in sliding of layers and lubricant of graphite.

- 1 atom thick

- Very flexible layers

Uses of graphite

-Lead pencils

-Graphene is a hexagonal covalent bond of carbon.

-Layers of graphene form Graphite

Physical Properties

-Silver/gray color

- Low hardness, very flexible flakes

-Hexagonal plates

-Opaque

- Low weight

Chemical Properties

-Hexagonal layers

-Conductor of electricity due to london forces

Physical Properties:

• Soft, slippery and brittle which is typical of covalent substances.

• Not an electrical insulator because there’s no movement between electrons

• Insoluble in water because there’s a weak Van der Waals attraction between carbon atoms and water molecules.

• Low melting point which is typical of covalent substances.

Chemical Properties:

• The C60 molecule is extremely stable, it can withstand high temperatures and pressures.

• Buckyballs do not bond to one another. Instead they stick together through Van der Waals forces.

• Carbon nanotube’s sidewalls are electrically polarizable; this allows polar molecules to adhere to their surfaces.

• When molecules bond non-covalently to the carbon nanotube surface, they often cause subtle changes in the electronic structure of the tubes.

• Carbon atoms in nanotubes can covalently bond to other atoms or molecules creating a new molecule with customized properties.

Structure:

• The basic C60 (Buckminsterfullerene) structure consists of 60 carbon atoms that link together to form a hollow cage-like structure. The structure consists of 32 faces. 20 are hexagons and 12 are pentagons. No two pentagons will share a vertex.

• Single-wall carbon nanotubes, are single layers of graphite (graphene) rolled up into a seamless tube.

• Graphene consists of a hexagonal structure like chicken wire

Appearance to the eye:

• Too small to be seen with your eyes but because it is found in soot it can be found as a black powder.

Chemical structure of Graphite

Physical structure of Graphite

Fun Facts of Diamonds!

Allotropes

Physical Properties

• Graphene is only soluble in water when oxidized
• It can conduct electricity due to each C atom having a pi electron
• It has a very high melting pt. of 4,900 K
• The small and tight carbon bonds in graphene allow it to be extremely strong & resistant to strain
• A single-layer, so graphene is very flexible
• When it's in a single-layer, graphene is clear, making it optimal for future phone screens
• It absorbs 2.3% of white light so it can be seen with the naked eye

• Diamonds can be synthetically made
• Diamonds are billions of years old!
• Diamonds form about 100 miles below ground and are carried to Earth's surface by deep volcanic eruptions

Graphene could be used in the future as a touch screen

Physical Appearance of Diamond

Citations

Structure of SiO2

• Most always transparent
• Comes in all different shapes and sized
• They are often seen in jewelry
• Diamonds are also used in cutting, drilling and polishing
• Shiny

Each of two or more different physical forms in which an element can exist

http://diamondsanddrillbits.blogspot.com/2012/11/physical-and-chemical-properties-of.html

https://www.quora.com/What-are-the-physical-and-chemical-properties-of-diamond-and-graphite

http://www.brilliantearth.com/news/15-amazing-facts-about-diamonds/

http://www.graphenea.com/pages/graphene-properties#.V_vPpvkrLIU

http://www.graphene.manchester.ac.uk/explore/what-can-graphene-do/

http://www.nanowerk.com/what_is_graphene.php

http://www.zdnet.com/article/the-10-strangest-facts-about-graphene/

http://www.azonano.com/article.aspx?ArticleID=983

http://phycomp.technion.ac.il/~talimu/structure.html

http://www.understandingnano.com/nanotubes-carbon-properties.html

http://www.cnanotech.com/pages/resources_and_news/press_release_archive/press_story_TSA.html

http://www.azom.com/article.aspx?ArticleID=3499

https://en.wikipedia.org/wiki/Van_der_Waals_force

http://www.pa.msu.edu/cmp/csc/ntproperties/equilibriumstructure.html

http://ibchem.com/IB/ibnotes/full/bon_htm/14.4.htm

https://en.wikipedia.org/wiki/Buckminsterfullerene#Properties

https://en.wikipedia.org/wiki/Fullerene

https://en.wikipedia.org/wiki/Carbon_nanotube

chemical properties

• insoluble in water & does not conduct electricity.
• These properties result from the very strong covalent bonds that hold the silicon & oxygen atoms in the giant covalent structure.

Wearable Graphene Tech

Bon Structure of Graphene

Graphene Sheet

Allotropes

Alyzza, Annelise, Carly, Elizabeth & Tiara