C70 fullerene

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C70 fullerene
Preferred IUPAC name
(C70-D5h(6))[5,6]Fullerene [1]
Other names
Fullerene-C70, rugbyballene
3D model (JSmol)
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PubChem CID
  • 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)64
  • InChI=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)64
  • 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=C27
Molar mass 840.770 g·mol−1
AppearanceDark needle-like crystals
Density 1.7 g/cm3
Melting point sublimates at ~850 °C [2]
insoluble in water
Band gap 1.77 eV [3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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.


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]


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 > 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]


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]



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. Fullerene C70.png
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−
, whereas oxidation is irreversible. The first reduction requires around 1.0 V (Fc/Fc+
), indicating that C70 is an electron acceptor. [9]


Saturated solubility of C70 (S, mg/mL) [10]
SolventS (mg/mL)
1,2-dichlorobenzene 36.2
carbon disulfide 9.875
xylene 3.985
toluene 1.406
benzene 1.3
carbon tetrachloride 0.121
n-hexane 0.013
cyclohexane 0.08
pentane 0.002
octane 0.042
decane 0.053
dodecane 0.098
heptane 0.047
isopropanol 0.0021
mesitylene 1.472
dichloromethane 0.080

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]


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. [3] [12]

All phases of C70 form brownish crystals with a bandgap of 1.77 eV; [3] 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 NoPearson
a (nm)b (nm)c (nm)ZDensity
Monoclinic P21/m11mP5601.9961.8511.9968
Hexagonal P63/mmc194hP1401.0111.0111.85821.70
Cubic Fm3m225cF2801.4961.4961.49641.67

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Fullerene Allotrope of carbon

A fullerene is an allotrope of carbon whose molecule consists of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecule may be a hollow sphere, ellipsoid, tube, or many other shapes and sizes. Graphene, which is a flat mesh of regular hexagonal rings, can be seen as an extreme member of the family.

Harry Kroto English chemist

Sir Harold Walter Kroto, known as Harry Kroto, was an English chemist. He shared the 1996 Nobel Prize in Chemistry with Robert Curl and Richard Smalley for their discovery of fullerenes. He was the recipient of many other honors and awards.

Richard Smalley American chemist

Richard Errett Smalley was the Gene and Norman Hackerman Professor of Chemistry and a Professor of Physics and Astronomy at Rice University. In 1996, along with Robert Curl, also a professor of chemistry at Rice, and Harold Kroto, a professor at the University of Sussex, he was awarded the Nobel Prize in Chemistry for the discovery of a new form of carbon, buckminsterfullerene, also known as buckyballs. He was an advocate of nanotechnology and its applications.

Robert Curl American chemist

Robert Floyd Curl Jr. is an American University Professor Emeritus, Pitzer–Schlumberger Professor of Natural Sciences Emeritus, and Professor of Chemistry Emeritus at Rice University. He was awarded the Nobel Prize in Chemistry in 1996 for the discovery of the nanomaterial buckminsterfullerene, along with Richard Smalley and Harold Kroto of the University of Sussex.

Buckminsterfullerene Carbon allotrope

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Fullerene chemistry

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Volleyballene term refers to a chemical compound that is a new type of 3D hollow molecule composed of carbon and transition metals, the name is a reference to fullerenes. It is the first buckyball compound to be spiked with scandium atoms. The main feature of these substances is that metal atoms are part of the framework and they are not deposited on the surface of the molecule. The incorporation of the metal atoms avoids their clustering and confers to volleyballene with sites to attach hydrogen mainly. The history of volleyballenes dates from its first prediction in 2016 by Jing Wang et al. A further study based on Density functional Theory (DFT) carried out by Tlahuice-Flores in the same year supports the prediction and provides with Infrared, Raman and UV spectra of the structure for its experimental detection. The structure is described as one Sc8 cluster holding 12 scandium atoms linked to six C10 units on each face. The chemical formula C60Sc20 is close related to C80 fullerene and it has a large HOMO-LUMO gap of 1.47 eV. Further hydrogenation of volleyballene reported a 70-H structure with an adsorption energy of circa -0.11 eV/H2. Moreover, it is expected that the adsorption-desorption reaction can be reached at ambient temperature. Potential use of volleyballenes is hydrogen storage even at ambient conditions.  

Solubility of fullerenes

The solubility of fullerenes is generally low. Carbon disulfide dissolves 8g/L of C60, and the best solvent (1-chloronaphthalene) dissolves 53 g/L. up Still, fullerenes are the only known allotrope of carbon that can be dissolved in common solvents at room temperature. Besides those two, good solvents for fullerenes include 1,2-dichlorobenzene, toluene, p-xylene, and 1,2,3-tribromopropane. Fullerenes are highly insoluble in water, and practically insoluble in methanol.


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