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Carbon ( C ) PowerPoint Presentation
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Carbon ( C )

Carbon ( C )

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Carbon ( C )

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  1. Carbon ( C ) • Pure Carbon exists in four different crystalline forms • Diamond, Graphite, Fullerenes, Nanotubes • Other common carbon: Amorphous carbon • charcoals, soot and glassy carbon (microcrystalline forms of graphite) Graphite Diamond C60

  2. Carbon Graphite Diamond 100 kbar, 1200~2800 K Graphite --------------------------------> diamond Cr, Fe or Ni A route published in Science Fullerene Bucky Tube

  3. Graphite • Soft and black and the stable,common,form of carbon. • Very light and resistant • More 2D like; SP2 Orbitals. Atom is at the corners of fused hexagon in parallel layers • Strong bonds within layers and weak bond between layers • Good conductor of electricity

  4. Graphite

  5. Diamond • Hard and transparent and the unusual form of carbon. • Strong thermal conductivity • More 3D like behavior; SP3 orbital. Atom is bound to four other carbon atoms in a regular repetitive pattern. • Strong covalent bonding in 3 dimensions • Bad electrical conductor (Diamonds are not forever!!) It will turn into graphite (given time). (Faster if you heat it up or bombard it with high energy ions.)

  6. Diamond • Abrasive • Gem

  7. Fullerenes C60 • Discovered in 1985 by Harry Kroto University of Sussex, England • Richard Smalley and Robert Curl Jr Rice University, Texas • 1996 Nobel Prize in Chemistry H.Kroto R. Smalley R. Curl

  8. Smalley's apparatus for generating and detecting buckyball.

  9. Schematic of a mass spectrometer

  10. “..in the field of Observation, chance only favors the prepared mind” Louis Pasteur

  11. C60 Bucky Ball; fullerene • J.R. Heath, S.C. O'Brien, H.W. Kroto, • R.F. Curl, R.E. Smalley, • Nature 318 , 162, (1985)

  12. Carbon sphere resembles the surface of a soccer ball!! 12 pentagons and 20 hexagons Fullerenes C60

  13. Fullerene • C60 • - A third allotropic form of very stable spheres(1985) • - Formed when graphite is evaporated in an inert atmosphere. • - Assumed C60 consists of 12 pentagons and 20 hexagons with carbon atoms at each corner, as a soccer ball. • - Names • New carbon ball • C60 • Buckminsterfullerene • ( R.Buckminster Fuller : The Geodesic dome 1967 ) • Buckyball

  14. What is happening in current research with Buckyball? Fullerene Pyrrolidine and Osmium Tetroxide derivatives of C60. Model of C60 docked in the binding site of HIV-1 protease

  15. Rational Side of Materials Chemistry: Rational Doping: C60 insulator Semiconductor Supercondctor La2CuO4 Magnetic insulator Bad Metal Superconductor K K3C60

  16. Nanotubes C1,000,000 and beyond • Discoverer: Sumio Iijima • Carbon Nanotubes (CNT) • 1991 multiwalled CNT coaxial cylinders with a hollow core • 1993 single-walled CNT • Roll up sheets of hexagons

  17. Diameter ~ 1-30 nm Length ~ microns Interlayer Spacing 0.347 nm Graphite interlayer spacing 0.337 nm Nanotubes C1,000,000 and beyond IBM

  18. NUS Surface Science Laboratory Do C60 and CNT really exist? Seeing is believing Yacobson and Smalley Richard Smalley Image Gallery

  19. Depending on the orientation of the six-membered ring in the honeycomb lattice relative to the tube-axis, there are three classes of carbon Nanotube Armchair, Zigzag and Chiral Their names are derived from the shape of the cross-sectional ring at the edge of the tube. Three Classes of Carbon Nanotubes

  20. Armchair Zig-Zag Chiral Three Classes of Carbon Nanotubes

  21. Arc discharge Laser Ablation Catalytic decomposition of carbon monoxide or hydrocarbons Chemical vapor deposition How do we make them?

  22. Arc Discharge

  23. Catalytic Decomposition Catalyst Co/La2O3 CO/ CH4 CNT 600-750 oC H, CH4 or CO Quartz Tube 2CO C + CO2 CH4 C + 2H2 Temperature Programmable Furnace

  24. Strongest and stiffest synthetic Fabrics: It can be stretched by almost 30% without breaking; 100 times as strong as steel per unit weight. Most of the twisting, bending and compressing are reversible. Suitable for making cables, airplane skin Cables extending all the way into space!!! (most ropes would break under their own weight!!) Mechanical Properties of CNT

  25. Electrical Properties of different types of CNTs Armchair CNT has good electrical conductivity as a metal. (independent of diameter) 1/3 Zigzag CNT Metal 2/3 Chiral CNT behave as semiconductor Electrical Properties of CNT

  26. Arranging CNT into electronic circuitry. Nanotube Quantum Wire

  27. Thermal Properties Superior thermal conductivity along the tubes: Heat energy in CNT is carried out by sound waves, which travel straight down individual CNT at ~ 10,000 m/s better heat sinks for microelectronic devices. Thermal Properties of CNT

  28. AFM Manipulation of CNT

  29. Nanostraws Nanotweezers Nano test tubes Nano- ……. Based on CNT • Nanobalance • Nanofilters

  30. carbon fibers

  31. Intercalation compounds of graphite

  32. Carbides (p155) • Ionic Carbides • Alkali and alkaline earth metals, Aluminum Such as Al4C3 and CaC2 2. Ionic character suggested by theur ractuon with water

  33. Carbides (p155) • Interstitial Carbides • Character: mainly transition metals • C atoms occupy the tetrahedral holes in the close-packed arrays • Very hard, good conductivity, high melting point • 1st transition metals: hydrolyzed

  34. Carbides (p155) • Covalent Carbides • The metalloids • Silicon and boron: SiC and B4C • SiC: structure similar as diamond • extremely hard, close to diamond, used as cutting tools and abrasives • Chemically inert

  35. Carbon Monoxide (p155) • Preparation in lab: formic acid with concentric sulphuric acid • Important properties: :C=O: • as reducing agent or synthetic material • Coordinate to transition metals, Such as nickel tetracarbonyl Ni(CO)4 or [Cu(NH3)2(CO)]Ac • The toxicity: combined with Fe atom in hemoglobin

  36. Carbon dioxide and carbonic acid (p156) • Involved in geochemical cycle and photosynthesis O=C=O 2π34 • ‘dry ice’: sublimes -78.5 oC • Note for Carbonic acid: • Ka1 = 4.16E-7, incorrect, because the hydration reaction of CO2 is slow. The correct value is 2E-4 • The thermo-stability, solubility of salts

  37. Carbon dioxide and carbonic acid • Note: 3. Hydrolysis: basity • Ba2+, Ca2+, Ag+: form carbonate • Fe3+, Cr3+, Al3+: form hrdroxide • Cu2+, Zn2+, Pb2+, Mg2+: form (condition) hydrox-carbonate

  38. Cyanides and Related Compounds (p158) • CN–, OCN–, SCN– pseudo-halogen • Resemblance to halogens • Molecules: (CN)2, (OCN)2, (SCN)2; but polymerization, such as (CN)x,(SCN)x • Disproportionation: (CN)2 + OH– OCN– + CN– + H2O • Coordination abilities • Molecule oxidizing ability and anion reducing ability: F2(OCN)2 Cl2 Br2 (CN)2 (SCN)2 I2

  39. Carbon disulfide • Preparation: CH4 + S CS2 + H2S • Very toxic liquid (bp 46 oC) • Very reactive: nucleophilic reaction such thiocarbonate CS32–, C3S52–, (CN)2C2S22– 1000 oC Al2O3