C60 has the shape of a truncated icosahedron and belongs to the Ih<\/sub> point group. Its sixty carbon atoms are symmetry-equivalent. C70 is elongated along one molecular axis, contains 25 hexagons and 12 pentagons, and has D5h<\/sub> symmetry. Its carbon atoms occupy five symmetry-distinct environments.<\/p>\n\n\n\n Gas-phase electron-diffraction measurements are consistent with the D5h<\/sub> structure of free C70 molecules and show that describing C70 requires substantially more structural parameters than describing C60.[2]<\/a><\/sup> The elongated cage should therefore not be treated simply as \u201cC60 plus ten carbon atoms\u201d; it is a different molecular framework.<\/p>\n\n\n\n The twelve pentagons required to close a conventional fullerene cage are present in both molecules. C60 contains twenty hexagons, whereas C70 contains twenty-five. A useful geometric description of C70 is a C60-like cage extended by a belt of five additional hexagons around its equatorial region.<\/p>\n\n\n\n The higher symmetry of C60 creates a relatively uniform molecular surface. C70 has polar, equatorial and intermediate regions that are not chemically equivalent. Different carbon\u2013carbon bonds can therefore present different local curvature, orbital character and reaction accessibility.<\/p>\n\n\n\n This distinction matters in synthesis. A monoaddition to C60 can already produce different bond-connectivity outcomes, but addition to C70 introduces an additional problem: the reagent may attack several nonequivalent sites on the elongated cage. The resulting product can be a mixture of site isomers even when the degree of addition is controlled.<\/p>\n\n\n\n Consequently, a C70 derivative should not be characterized only by a parent-ion mass or nominal addend count. Researchers may need chromatographic separation, nuclear magnetic resonance, absorption spectroscopy and structural evidence capable of distinguishing the relevant site isomers.<\/p>\n\n\n\n Molecular symmetry affects which electronic transitions are allowed and how strongly they appear in an absorption spectrum. C60 has several symmetry-forbidden or weak low-energy transitions. The lower symmetry of C70 changes the transition pattern and generally gives C70 a more pronounced response across parts of the visible spectrum.<\/p>\n\n\n\n This does not create one universal ratio by which C70 \u201cabsorbs more light.\u201d The result depends on wavelength, solvent, concentration, aggregation state, optical path length and whether the comparison concerns pristine cages or functionalized derivatives.<\/p>\n\n\n\n Aggregation can change the spectrum further. Ghosh and colleagues found that C70 formed clusters in selected solvent mixtures and that the associated optical changes were reversible and dependent on solubility conditions.[3]<\/a><\/sup> A spectrum measured from an aggregated dispersion should therefore not be interpreted automatically as the spectrum of isolated C70 molecules.<\/p>\n\n\n\n For quantitative comparison, researchers should specify the solvent or matrix, concentration, temperature, spectral range and extinction-coefficient basis. Color alone cannot establish purity, molecular dispersion or suitability for a photochemical experiment.<\/p>\n\n\n\n Neither pristine C60 nor pristine C70 is meaningfully water-soluble as an isolated neutral molecule under ordinary conditions. Both dissolve to varying degrees in selected organic solvents, particularly several aromatic or highly polarizable solvents.<\/p>\n\n\n\n C70 solubility varies over several orders of magnitude depending on the solvent. Experimental measurements by Sivaraman and colleagues found values ranging from very low solubility in pentane to much greater solubility in selected chlorinated aromatic solvents at the tested temperature.[4]<\/a><\/sup><\/p>\n\n\n\n These historical measurements are useful reference points, not guaranteed formulation values. Solubility can change with temperature, solvent purity, fullerene composition, crystal history and measurement method. Mixtures of solvents may also produce aggregation even when the fullerene initially appears dissolved.<\/p>\n\n\n\n Researchers should distinguish four states:<\/p>\n\n\n\n These states can produce different spectroscopy, reactivity and film morphology. The site\u2019s guide to the solubility of pristine C60 and C70<\/a> provides additional handling context.<\/p>\n\n\n\n Both C60 and C70 can accept multiple electrons through successive reduction steps, which is one reason they are investigated in molecular electronics, electrochemistry and donor\u2013acceptor systems. Their reduction potentials and spectra are not identical, however.<\/p>\n\n\n\n Dubois and colleagues used spectroelectrochemistry to study C60, C70 and several reduced fullerene states.[5]<\/a><\/sup> Such measurements demonstrate that the cages form distinct anionic species, but reduction values must be interpreted with their solvent, supporting electrolyte, reference electrode, temperature and measurement method.<\/p>\n\n\n\n Electron affinity, solution reduction potential, molecular orbital energy and solid-state transport level are related but non-equivalent quantities. A gas-phase electron affinity cannot be inserted directly as a device LUMO level, and a cyclic-voltammetry result cannot by itself predict charge mobility in a thin film.<\/p>\n\n\n\n C70 should also not be described as universally more reactive or a better electron acceptor than C60. The relevant comparison depends on the reaction or electronic system, its environment and the derivative being studied.<\/p>\n\n\n\n Functionalization adds covalent groups to the fullerene cage. It may introduce a synthetic handle, change solution processing, alter intermolecular packing or create a donor\u2013acceptor material. Once an addend is attached, the product is no longer pristine C70.<\/p>\n\n\n\n The reduced symmetry of C70 makes site selection particularly important. Different bonds can produce \u03b1-, \u03b2- or other site-isomeric products, depending on the reaction classification used. Reaction conditions, reagent structure and solvent can affect the product distribution.<\/p>\n\n\n\n Matsumoto and colleagues showed that changing the steric structure of an addend could improve regioselectivity in the preparation of [70]PCBM-related derivatives.[6]<\/a><\/sup> This illustrates why the purity of the C70 precursor does not determine the regioisomeric purity of the final derivative.<\/p>\n\n\n\n A derivative-development program should separately evaluate:<\/p>\n\n\n\n The analytical package for a C70 derivative is therefore more extensive than a precursor HPLC percentage.<\/p>\n\n\n\n PC71BM\u2014also written PC70<\/sub>BM or [70]PCBM\u2014is a methanofullerene derivative synthesized from C70. The attached phenyl-butyric acid methyl ester group changes its molecular mass, symmetry, solubility and solid-state organization.<\/p>\n\n\n\n PC71BM is not a \u201cC70 purity grade,\u201d and a C70 product should not be marketed as PC71BM unless the functionalization, purification and structural characterization have actually been performed. Conversely, a photovoltaic result obtained with PC71BM cannot be attributed directly to pristine C70 powder.<\/p>\n\n\n\n Hadad and colleagues reported the synthesis of PC61BM and PC71BM mono-adducts through microwave-assisted cyclopropanation, illustrating that both materials require chemical conversion from their respective parent cages.[7]<\/a><\/sup><\/p>\n\n\n\n C70-based derivatives are often selected in organic photovoltaic research partly because their absorption differs from analogous C60 derivatives. Their practical effect nevertheless depends on the donor, blend composition, morphology, solvent, additives, annealing, layer thickness and device architecture.<\/p>\n\n\n\n A result obtained from a particular PC71BM donor blend does not establish that PC71BM will outperform PC61BM in every device. The article on fullerenes in organic photovoltaics and molecular electronics<\/a> examines these device-level variables separately.<\/p>\n\n\n\n C70 and its derivatives have been investigated in photochemistry because the cage can populate excited states and participate in energy or electron transfer. Under defined conditions, a C70 system may generate reactive oxygen species. Under different conditions, a fullerene material may interact with radical species through other pathways.<\/p>\n\n\n\n Photochemical behavior depends on molecular structure, functionalization, aggregation, oxygen concentration, wavelength, irradiance, exposure time and surrounding medium. It should not be converted into a general claim that C70 is a stronger antioxidant, safer photosensitizer or more biologically active material than C60.<\/p>\n\n\n\n Biomedical research commonly uses functionalized or formulated fullerene materials rather than dry pristine C70. Findings involving a water-compatible derivative, nanocomplex or targeted conjugate apply to that test article. They do not establish that raw C70 crosses the blood\u2013brain barrier, treats neurodegenerative disease or selectively destroys tumors.<\/p>\n\n\n\n The European Commission\u2019s Scientific Committee on Consumer Safety concluded in its 2023 opinion that genotoxic potential could not be excluded for C60 and C70 and identified unresolved concerns involving impurities, stability, radical generation, phototoxicity and exposure.[8]<\/a><\/sup> Raw-material purity therefore cannot establish biomedical or cosmetic safety.<\/p>\n\n\n\n C70 is generally formed alongside C60 and other carbon species in carbon-vaporization or combustion environments. The resulting soot is not pure C70. It must be extracted, separated, purified and characterized.<\/p>\n\n\n\n Because C60 is often a major component of fullerene extracts, recovering C70 requires separation from a chemically similar cage. Chromatography, selective complexation, crystallization and combinations of purification techniques have been investigated for this purpose.<\/p>\n\n\n\n The production route does not by itself determine final purity. Arc discharge does not inherently require transition-metal catalysts to form empty C60 or C70 cages, and combustion does not prove zero metals or zero residual solvents. These attributes require batch-specific analytical evidence when they are relevant.<\/p>\n\n\n\n The guide to arc-discharge fullerene synthesis<\/a> explains the distinction between fullerene formation, soot composition and final purified material.<\/p>\n\n\n\n No single analytical method establishes every relevant attribute. A useful characterization plan starts with the intended experiment and its likely failure modes.<\/p>\n\n\n\n HPLC can separate and quantify detectable soluble fullerene species under the selected chromatographic method. It may distinguish C70 from C60 and certain higher fullerene or derivative components, but the result depends on column chemistry, mobile phase, detector, integration and calculation basis.<\/p>\n\n\n\n Mass spectrometry can support molecular identity by detecting the expected C70 ion pattern. It does not independently establish site-isomer purity, residual solvents or the absence of every element. Carbon-13 NMR is particularly informative for molecular symmetry and may help characterize functionalized products, although sensitivity and sample quantity can be limiting.<\/p>\n\n\n\n UV\u2013visible spectroscopy provides an additional identity and solution-state check. Unexpected band shape or scattering may indicate aggregation or another component, but a spectrum alone is not a complete purity assay.<\/p>\n\n\n\n Elemental analysis, gas chromatography, thermal analysis or other methods may be added when metals, volatile residues, thermal behavior or processing stability matter. The site\u2019s fullerene characterization guide<\/a> explains why these techniques provide complementary evidence.<\/p>\n\n\n\n C70 is a logical candidate when the elongated cage, lower symmetry, visible-region absorption or differentiated reaction sites are relevant to the experimental design. It may also be selected as the precursor for a defined C70 derivative.<\/p>\n\n\n\n C60 may be more appropriate where high symmetry, simpler site equivalence, a broader established reaction literature or compatibility with an existing C60 process is important. Lower material cost or easier separation may also matter during early screening, but commercial considerations should not replace scientific requirements.<\/p>\n\n\n\n The selection should be made through controlled comparison. Researchers should hold the surrounding formulation or device process as constant as practicable, verify the identity of each material, and avoid comparing pristine C60 with a functionalized C70 derivative as though only the cage size had changed.<\/p>\n\n\n\n The Fullerene supplies defined C70 and C60 materials for fullerene chemistry, spectroscopy, electrochemistry, derivative synthesis and advanced-materials research. Supported by a globally respected scientific research network, The Fullerene represents a leading level of fullerene products and technical capability in Asia.<\/p>\n\n\n\n XCT can discuss fullerene identity, intended experimental use, purity basis and available analytical information. The structure, purity and performance of any derivative, formulation, thin film or device must be established within the customer\u2019s actual preparation and test system.<\/p>\n\n\n\n Share the intended reaction, optical experiment, material comparison or derivative-development program with The Fullerene. XCT can discuss suitable C70 or C60 starting materials for controlled scientific and industrial research.<\/p>\n\n\n\n Discuss Your C70 Material Requirement<\/a><\/p>\n\n\n\n C60 is a highly symmetrical, near-spherical Ih<\/sub> cage, while C70 is an elongated D5h<\/sub> cage with five groups of symmetry-distinct carbon atoms.<\/p>\n\n\n\n C70 generally has more pronounced absorption across parts of the visible spectrum because of its lower symmetry, but the comparison depends on wavelength, solvent, concentration, aggregation and whether pristine cages or derivatives are tested.<\/p>\n\n\n\n No. PC71BM is a covalently functionalized C70 derivative with different molecular mass, solubility, symmetry, isomer composition and analytical requirements.<\/p>\n\n\n\n No. C70 may be useful for particular optical or derivative-synthesis objectives, while C60 may be preferable where higher symmetry, simpler site equivalence or an established C60 process matters.<\/p>\n\n\n\n No. Raw-material purity does not establish formulation stability, biological exposure, toxicology, clinical efficacy or regulatory suitability for a finished product.<\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" C60 and C70 are the two most widely isolated molecular fullerenes, but they are not interchangeable versions of the same carbon material. C60 contains sixty carbon atoms in a highly symmetrical cage, while C70 contains seventy carbon atoms in a more elongated structure. That change affects molecular symmetry, spectroscopy, solid-state packing, reaction-site equivalence and the […]<\/p>\n","protected":false},"author":1,"featured_media":2981,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_gspb_post_css":"","footnotes":""},"categories":[45],"tags":[115],"class_list":["post-2208","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-markets","tag-buckminsterfullerene-c70"],"blocksy_meta":[],"acf":[],"_links":{"self":[{"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/posts\/2208","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/comments?post=2208"}],"version-history":[{"count":3,"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/posts\/2208\/revisions"}],"predecessor-version":[{"id":3167,"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/posts\/2208\/revisions\/3167"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/media\/2981"}],"wp:attachment":[{"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/media?parent=2208"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/categories?post=2208"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.thefullerene.com\/zh\/wp-json\/wp\/v2\/tags?post=2208"}],"curies":[{"name":"\u5de5\u4f5c\u6587\u4ef6","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}How Does C70 Differ Structurally from C60?<\/h2>\n\n\n\n
![\"\"](\"https:\/\/www.thefullerene.com\/wp-content\/uploads\/2026\/07\/chatgpt-image-2026\u5e747\u67083\u65e5-10_21_47-1024x576.png\" "\\"\\"")
C70 and C60 Have Different Optical Spectra<\/h2>\n\n\n\n
![\"Solubility](\"https:\/\/www.thefullerene.com\/wp-content\/uploads\/2026\/07\/chatgpt-image-2026\u5e747\u67087\u65e5-16_48_58-1024x576.png\" "\\"\\"")
Are C70 and C60 Equally Soluble?<\/h2>\n\n\n\n
![\"\"](\"https:\/\/www.thefullerene.com\/wp-content\/uploads\/2026\/07\/chatgpt-image-2026\u5e747\u67087\u65e5-15_04_34-1024x576.png\" "\\"\\"")
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Electron Acceptance and Electrochemistry<\/h2>\n\n\n\n
C70 Functionalization Is More Regioisomerically Complex<\/h2>\n\n\n\n
![\"UV-visible](\"https:\/\/www.thefullerene.com\/wp-content\/uploads\/2026\/05\/ChatGPT-Image-2026\u5e747\u670817\u65e5-11_14_36-1024x576.png\" "\\"\\"")
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Pristine C70 and PC71BM Are Different Materials<\/h2>\n\n\n\n
Can C70 Be Used in Photochemical or Biomedical Research?<\/h2>\n\n\n\n
How C70 Is Produced and Separated<\/h2>\n\n\n\n
How to Characterize a C70 Material<\/h2>\n\n\n\n
When Should Researchers Choose C70 Instead of C60?<\/h2>\n\n\n\n
C70 Research Materials from The Fullerene<\/h2>\n\n\n\n
Discuss a C70 Research Requirement<\/h2>\n\n\n\n
Frequently Asked Questions<\/h2>\n\n\n\n
What is the main structural difference between C70 and C60?<\/h3>\n\n\n\n
Does C70 absorb more visible light than C60?<\/h3>\n\n\n\n
Is PC71BM the same as high-purity C70?<\/h3>\n\n\n\n
Is C70 better than C60 for every research application?<\/h3>\n\n\n\n
Does high-purity C70 establish biomedical or cosmetic safety?<\/h3>\n\n\n\n
References<\/h2>\n\n\n\n
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