C70 fullerene is the fullerene molecule consisting of 70 carbon atoms. It is a cage-like fused-ring structure which resembles a rugby ball, made of 25 hexagons and 12 pentagons, with a carbon atom at the vertices of each polygon and a bond along each polygon edge. A related fullerene molecule, named buckminsterfullerene (C60 fullerene), consists of 60 carbon atoms.
Theoretical predictions of buckyball molecules appeared in the late 1960s to early 1970s,[5] but they went largely unnoticed. In the early 1970s, the chemistry of unsaturated carbon configurations was studied by a group at the University of Sussex, led by Harry Kroto and David Walton. In the 1980s a technique was developed by Richard Smalley and Bob Curl at Rice University, Texas to isolate these substances. They used laser vaporization of a suitable target to produce clusters of atoms. Kroto realized that by using a graphite target.[6]
C70 was discovered in 1985 by Robert Curl, Harold Kroto and Richard Smalley. Using laserevaporation of graphite they found Cn clusters (for even n with n > 20) of which the most common were C60 and C70. For this discovery they were awarded the 1996 Nobel Prize in Chemistry. The discovery of buckyballs was serendipitous, as the scientists were aiming to produce carbon plasmas to replicate and characterize unidentified interstellar matter. Mass spectrometry analysis of the product indicated the formation of spheroidal carbon molecules.[5]
SynthesisEdit
In 1990, K. Fostiropoulos, W. Krätchmer and D. R. Huffman developed a simple and efficient method of producing fullerenes in gram and even kilogram amounts which boosted fullerene research. In this technique, carbon soot is produced from two high-purity graphite electrodes by igniting an arc discharge between them in an inert atmosphere (helium gas). Alternatively, soot is produced by laser ablation of graphite or pyrolysis of aromatic hydrocarbons. Fullerenes are extracted from the soot using a multistep procedure. First, the soot is dissolved in appropriate organic solvents. This step yields a solution containing up to 70% of C60 and 15% of C70, as well as other fullerenes. These fractions are separated using chromatography.[7]
PropertiesEdit
MoleculeEdit
The C70 molecule has a D5h symmetry and contains 37 faces (25 hexagons and 12 pentagons) with a carbon atom at the vertices of each polygon and a bond along each polygon edge. Its structure is similar to that of C60 molecule (20 hexagons and 12 pentagons), but has a belt of 5 hexagons inserted at the equator. The molecule has eight bond lengths ranging between 0.137 and 0.146 nm. Each carbon atom in the structure is bonded covalently with 3 others.[8]
The structure of C70 molecule. Red atoms indicate five hexagons additional to the C60 molecule.
C70 can undergo six reversible, one-electron reductions to C6− 70, whereas oxidation is irreversible. The first reduction requires around 1.0 V (Fc/Fc+ ), indicating that C70 is an electron acceptor.[9]
Fullerenes are sparingly soluble in many aromatic solvents such as toluene and others like carbon disulfide, but not in water. Solutions of C70 are a reddish brown. Millimeter-sized crystals of C70 can be grown from solution.[11]
SolidEdit
Solid C70 crystallizes in monoclinic, hexagonal, rhombohedral, and face-centered cubic (fcc) polymorphs at room temperature. The fcc phase is more stable at temperatures above 70 °C. The presence of these phases is rationalized as follows. In a solid, C70 molecules form an fcc arrangement where the overall symmetry depends on their relative orientations. The low-symmetry monoclinic form is observed when molecular rotation is locked by temperature or strain. Partial rotation along one of the symmetry axes of the molecule results in the higher hexagonal or rhombohedral symmetries, which turn into a cubic structure when the molecules start freely rotating.[2][12]
All phases of C70 form brownish crystals with a bandgap of 1.77 eV;[2] they are n-type semiconductors where conductivity is attributed to oxygen diffusion into the solid from atmosphere.[13] The unit cell of fcc C70 solid contains voids at 4 octahedral and 12 tetrahedral sites.[14] They are large enough to accommodate impurity atoms. When electron-donating elements, such as alkali metals, are doped into these voids, C70 converts into a conductor with conductivity up to around 2 S/cm.[15]
^ abcThirunavukkuarasu, K.; Long, V. C.; Musfeldt, J. L.; Borondics, F.; Klupp, G.; Kamarás, K.; Kuntscher, C. A. (2011). "Rotational Dynamics in C70: Temperature- and Pressure-Dependent Infrared Studies". The Journal of Physical Chemistry C. 115 (9): 3646–3653. doi:10.1021/jp200036t.
^Eiji Ōsawa (2002). Perspectives of fullerene nanotechnology. Springer. pp. 275–. ISBN978-0-7923-7174-8. Retrieved 26 December 2011.
^Press Release. Nobel Prize Foundation. 9 October 1996
^Rao, C.N.R.; Seshadri, Ram; Govindaraj, A.; Sen, Rahul (1995). "Fullerenes, nanotubes, onions and related carbon structures". Materials Science and Engineering: R. 15 (6): 209–262. doi:10.1016/S0927-796X(95)00181-6.
^Buckminsterfullerene, C60. University of Bristol. Chm.bris.ac.uk (1996-10-13). Retrieved on 2011-12-25.
^ Talyzin, A.V.; Engström, I. (1998). "C70 in Benzene, Hexane, and Toluene Solutions". Journal of Physical Chemistry B. 102 (34): 6477. doi:10.1021/jp9815255.
^ abVerheijen, M.A.; Meekes, H.; Meijer, G.; Bennema, P.; De Boer, J.L.; Van Smaalen, S.; Van Tendeloo, G.; Amelinckx, S.; Muto, S.; Van Landuyt, J. (1992). "The structure of different phases of pure C70 crystals" (PDF). Chemical Physics. 166 (1–2): 287–297. Bibcode:1992CP....166..287V. doi:10.1016/0301-0104(92)87026-6. hdl:2066/99047.
^Fabiański, Robert; Firlej, Lucyna; Zahab, Ahmed; Kuchta, Bogdan (2002). "Relationships between crystallinity, oxygen diffusion and electrical conductivity of evaporated C70 thin films". Solid State Sciences. 4 (8): 1009–1015. Bibcode:2002SSSci...4.1009F. doi:10.1016/S1293-2558(02)01358-4.
^Haddon, R. C.; Hebard, A. F.; Rosseinsky, M. J.; Murphy, D. W.; Duclos, S. J.; Lyons, K. B.; Miller, B.; Rosamilia, J. M.; Fleming, R. M.; Kortan, A. R.; Glarum, S. H.; Makhija, A. V.; Muller, A. J.; Eick, R. H.; Zahurak, S. M.; Tycko, R.; Dabbagh, G.; Thiel, F. A. (1991). "Conducting films of C60 and C70 by alkali-metal doping". Nature. 350 (6316): 320–322. Bibcode:1991Natur.350..320H. doi:10.1038/350320a0. S2CID 4331074.
BibliographyEdit
Katz, E. A. (2006). "Fullerene Thin Films as Photovoltaic Material". In Sōga, Tetsuo (ed.). Nanostructured materials for solar energy conversion. Elsevier. pp. 361–443. ISBN978-0-444-52844-5.
August 25, 2023
fullerene, fullerene, fullerene, molecule, consisting, carbon, atoms, cage, like, fused, ring, structure, which, resembles, rugby, ball, made, hexagons, pentagons, with, carbon, atom, vertices, each, polygon, bond, along, each, polygon, edge, related, fulleren. C70 fullerene is the fullerene molecule consisting of 70 carbon atoms It is a cage like fused ring structure which resembles a rugby ball made of 25 hexagons and 12 pentagons with a carbon atom at the vertices of each polygon and a bond along each polygon edge A related fullerene molecule named buckminsterfullerene C60 fullerene consists of 60 carbon atoms C70 fullerene NamesPreferred IUPAC name C70 D5h 6 5 6 Fullerene 1 Other names Fullerene C70 rugbyballeneIdentifiersCAS Number 115383 22 7 Y3D model JSmol Interactive imageChEBI CHEBI 33195ChemSpider 17288599ECHA InfoCard 100 162 223PubChem CID 16131935CompTox Dashboard EPA DTXSID90151050InChI InChI 1S C70 c1 2 22 5 6 24 13 14 26 11 9 23 4 3 21 1 51 52 22 54 24 55 26 53 23 51 33 31 1 61 35 7 8 27 15 16 29 19 20 30 18 17 28 12 10 25 7 56 57 27 59 29 60 30 58 28 56 37 35 63 33 65 36 4 40 9 67 44 17 42 12 65 69 46 11 47 14 70 50 20 49 18 69 68 43 13 39 6 66 45 16 48 19 68 64 34 5 32 2 62 61 38 8 41 15 64Key ATLMFJTZZPOKLC UHFFFAOYSA NInChI 1 C70 c1 2 22 5 6 24 13 14 26 11 9 23 4 3 21 1 51 52 22 54 24 55 26 53 23 51 33 31 1 61 35 7 8 27 15 16 29 19 20 30 18 17 28 12 10 25 7 56 57 27 59 29 60 30 58 28 56 37 35 63 33 65 36 4 40 9 67 44 17 42 12 65 69 46 11 47 14 70 50 20 49 18 69 68 43 13 39 6 66 45 16 48 19 68 64 34 5 32 2 62 61 38 8 41 15 64Key ATLMFJTZZPOKLC UHFFFAOYAASMILES C12 C3C4 C5C6 C7C8 C9C 10 C 11C 12 C 13C 10 C 10C8 C5C1 C 10C1 C 13C5 C8C1 C2C1 C3C2 C3C 10 C 13C 14 C3C1 C8C1 C3C5 C 12C5 C8C 11 C 11C9 C7C7 C9C6 C4C2 C2C 10 C4C C29 C2 C6C C8C8 C9C6 C4C 13 C9C C 141 C3 C85 C 11 C27PropertiesChemical formula C 70Molar mass 840 770 g mol 1Appearance Dark needle like crystalsDensity 1 7 g cm3Melting point sublimates at 850 C 3 Solubility in water insoluble in waterBand gap 1 77 eV 2 Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Y verify what is Y N Infobox references It was first intentionally prepared in 1985 by Harold Kroto James R Heath Sean O Brien Robert Curl and Richard Smalley at Rice University Kroto Curl and Smalley were awarded the 1996 Nobel Prize in Chemistry for their roles in the discovery of cage like fullerenes The name is a homage to Buckminster Fuller whose geodesic domes these molecules resemble 4 Contents 1 History 2 Synthesis 3 Properties 3 1 Molecule 3 2 Solution 3 3 Solid 4 References 5 BibliographyHistory EditMain article Fullerene Harold Kroto Theoretical predictions of buckyball molecules appeared in the late 1960s to early 1970s 5 but they went largely unnoticed In the early 1970s the chemistry of unsaturated carbon configurations was studied by a group at the University of Sussex led by Harry Kroto and David Walton In the 1980s a technique was developed by Richard Smalley and Bob Curl at Rice University Texas to isolate these substances They used laser vaporization of a suitable target to produce clusters of atoms Kroto realized that by using a graphite target 6 C70 was discovered in 1985 by Robert Curl Harold Kroto and Richard Smalley Using laser evaporation of graphite they found Cn clusters for even n with n gt 20 of which the most common were C60 and C70 For this discovery they were awarded the 1996 Nobel Prize in Chemistry The discovery of buckyballs was serendipitous as the scientists were aiming to produce carbon plasmas to replicate and characterize unidentified interstellar matter Mass spectrometry analysis of the product indicated the formation of spheroidal carbon molecules 5 Synthesis EditIn 1990 K Fostiropoulos W Kratchmer and D R Huffman developed a simple and efficient method of producing fullerenes in gram and even kilogram amounts which boosted fullerene research In this technique carbon soot is produced from two high purity graphite electrodes by igniting an arc discharge between them in an inert atmosphere helium gas Alternatively soot is produced by laser ablation of graphite or pyrolysis of aromatic hydrocarbons Fullerenes are extracted from the soot using a multistep procedure First the soot is dissolved in appropriate organic solvents This step yields a solution containing up to 70 of C60 and 15 of C70 as well as other fullerenes These fractions are separated using chromatography 7 Properties EditMolecule Edit The C70 molecule has a D5h symmetry and contains 37 faces 25 hexagons and 12 pentagons with a carbon atom at the vertices of each polygon and a bond along each polygon edge Its structure is similar to that of C60 molecule 20 hexagons and 12 pentagons but has a belt of 5 hexagons inserted at the equator The molecule has eight bond lengths ranging between 0 137 and 0 146 nm Each carbon atom in the structure is bonded covalently with 3 others 8 The structure of C70 molecule Red atoms indicate five hexagons additional to the C60 molecule C70 can undergo six reversible one electron reductions to C6 70 whereas oxidation is irreversible The first reduction requires around 1 0 V Fc Fc indicating that C70 is an electron acceptor 9 Solution Edit Saturated solubility of C70 S mg mL 10 Solvent S mg mL 1 2 dichlorobenzene 36 2carbon disulfide 9 875xylene 3 985toluene 1 406benzene 1 3carbon tetrachloride 0 121n hexane 0 013cyclohexane 0 08pentane 0 002octane 0 042decane 0 053dodecane 0 098heptane 0 047isopropanol 0 0021mesitylene 1 472dichloromethane 0 080Fullerenes are sparingly soluble in many aromatic solvents such as toluene and others like carbon disulfide but not in water Solutions of C70 are a reddish brown Millimeter sized crystals of C70 can be grown from solution 11 Solid Edit Solid C70 crystallizes in monoclinic hexagonal rhombohedral and face centered cubic fcc polymorphs at room temperature The fcc phase is more stable at temperatures above 70 C The presence of these phases is rationalized as follows In a solid C70 molecules form an fcc arrangement where the overall symmetry depends on their relative orientations The low symmetry monoclinic form is observed when molecular rotation is locked by temperature or strain Partial rotation along one of the symmetry axes of the molecule results in the higher hexagonal or rhombohedral symmetries which turn into a cubic structure when the molecules start freely rotating 2 12 All phases of C70 form brownish crystals with a bandgap of 1 77 eV 2 they are n type semiconductors where conductivity is attributed to oxygen diffusion into the solid from atmosphere 13 The unit cell of fcc C70 solid contains voids at 4 octahedral and 12 tetrahedral sites 14 They are large enough to accommodate impurity atoms When electron donating elements such as alkali metals are doped into these voids C70 converts into a conductor with conductivity up to around 2 S cm 15 Some of the C70 solid phases 12 Symmetry Space group No Pearson symbol a nm b nm c nm Z Density g cm3 Monoclinic P21 m 11 mP560 1 996 1 851 1 996 8Hexagonal P63 mmc 194 hP140 1 011 1 011 1 858 2 1 70Cubic Fm3 m 225 cF280 1 496 1 496 1 496 4 1 67References Edit International Union of Pure and Applied Chemistry 2014 Nomenclature of Organic Chemistry IUPAC Recommendations and Preferred Names 2013 The Royal Society of Chemistry p 325 doi 10 1039 9781849733069 ISBN 978 0 85404 182 4 a b c Thirunavukkuarasu K Long V C Musfeldt J L Borondics F Klupp G Kamaras K Kuntscher C A 2011 Rotational Dynamics in C70 Temperature and Pressure Dependent Infrared Studies The Journal of Physical Chemistry C 115 9 3646 3653 doi 10 1021 jp200036t Eiji Ōsawa 2002 Perspectives of fullerene nanotechnology Springer pp 275 ISBN 978 0 7923 7174 8 Retrieved 26 December 2011 Press Release Nobel Prize Foundation 9 October 1996 a b Katz 363 Katz 368 Katz 369 370 Rao C N R Seshadri Ram Govindaraj A Sen Rahul 1995 Fullerenes nanotubes onions and related carbon structures Materials Science and Engineering R 15 6 209 262 doi 10 1016 S0927 796X 95 00181 6 Buckminsterfullerene C60 University of Bristol Chm bris ac uk 1996 10 13 Retrieved on 2011 12 25 Bezmel nitsyn V N Eletskii A V Okun M V 1998 Fullerenes in solutions Physics Uspekhi 41 11 1091 Bibcode 1998PhyU 41 1091B doi 10 1070 PU1998v041n11ABEH000502 Talyzin A V Engstrom I 1998 C70 in Benzene Hexane and Toluene Solutions Journal of Physical Chemistry B 102 34 6477 doi 10 1021 jp9815255 a b Verheijen M A Meekes H Meijer G Bennema P De Boer J L Van Smaalen S Van Tendeloo G Amelinckx S Muto S Van Landuyt J 1992 The structure of different phases of pure C70 crystals PDF Chemical Physics 166 1 2 287 297 Bibcode 1992CP 166 287V doi 10 1016 0301 0104 92 87026 6 hdl 2066 99047 Fabianski Robert Firlej Lucyna Zahab Ahmed Kuchta Bogdan 2002 Relationships between crystallinity oxygen diffusion and electrical conductivity of evaporated C70 thin films Solid State Sciences 4 8 1009 1015 Bibcode 2002SSSci 4 1009F doi 10 1016 S1293 2558 02 01358 4 Katz 372 Haddon R C Hebard A F Rosseinsky M J Murphy D W Duclos S J Lyons K B Miller B Rosamilia J M Fleming R M Kortan A R Glarum S H Makhija A V Muller A J Eick R H Zahurak S M Tycko R Dabbagh G Thiel F A 1991 Conducting films of C60 and C70 by alkali metal doping Nature 350 6316 320 322 Bibcode 1991Natur 350 320H doi 10 1038 350320a0 S2CID 4331074 Bibliography EditKatz E A 2006 Fullerene Thin Films as Photovoltaic Material In Sōga Tetsuo ed Nanostructured materials for solar energy conversion Elsevier pp 361 443 ISBN 978 0 444 52844 5 Retrieved from https en wikipedia org w index php title C70 fullerene amp oldid 1159377496, wikipedia, wiki, book, books, library,
