Chemistry
Graphite
Graphite is a form of carbon that is known for its softness and ability to conduct electricity. It is made up of layers of carbon atoms arranged in a hexagonal lattice structure. Graphite is commonly used in pencils, lubricants, and batteries.
Written by Perlego with AI-assistance
Related key terms
1 of 5
12 Key excerpts on "Graphite"
eBook - PDFHandbook of Carbon, Graphite, Diamonds and Fullerenes
Processing, Properties and Applications
- Hugh O. Pierson(Author)
- 2012(Publication Date)
- William Andrew(Publisher)
3 Graphite Structure and Properties 1~ THESTRUCTUREOFGraphite 1.1 General Considerations and Terminology The origin of the word Graphite is the Greek word graphein which means to write. Indeed, Graphite has been used to write (and draw) since the dawn of history and the first pencils were manufactured in England in the 15th century. In the 18th century, it was demonstrated that Graphite actually is an allotrope of carbon . Graphite is remarkable for the large variety of materials that can be produced from its basic form such as extremelystrong fibers, easily sheared lubricants, gas-tight barriers, and gas adsorbers. All these diverse materials have one characteristic in common: they are all built upon the trigonal Sp2 bonding of carbon atoms. Strictly speak ing, the term Graphite by itself describes an ideal material with a perfect Graphite structure and no defects whatsoever. However, it is also used commonly, albeit incorrectly, to describe graphitic materials. These materials are either graphitic carbons, that is, materials consisting of carbon with the Graphite structure, but with a number of structural defects, or non-graphitic carbons,that is, materials consisting of carbon atoms with the planar hexagonal networks of the Graphite structure, but lacking the crystallographic order in the c direction.l'l This is a fundamental difference and these two groups of materials are distinct in many respects, with distinct properties and different applications. 43 44 Carbon, Graphite, Diamond, and Fullerenes As a reminder and as mentioned in Ch. 1, the term carbon by itself should describe the element and nothing else. To describe a material, it is coupled with a qualifier, such as carbon black, activated carbon, ''vitreous carbon, amorphous carbon, and others. 1.2 Structure of the Graphite Crystal Graphite is composed of series of stacked parallel layer planes shown schematically in Fig. 3.1, with the trigonal Sp2 bonding described in Ch. 2, Sec.
eBook - PDFGraphene
Energy Storage and Conversion Applications
- Zhaoping Liu, Xufeng Zhou(Authors)
- 2014(Publication Date)
- CRC Press(Publisher)
18 2 Graphene of the softest materials, which is mainly ascribed to the different carbon atomic arrangement. Graphite has a layered, planar structure. In each layer, the carbon atoms are arrangement in a honeycomb lattice with separation of 0.142 nm, the dis-tance between graphene planes is 0.335 nm, and the planes are bonded to each other by weak van der Waals forces (Figure 1.1). The layered structure of Graphite allows sliding movement of the parallel graphene plates. Weak bonding between the plates determines the softness and self-lubricating properties of Graphite. Graphite is rarely found in the form of monocrystals; most Graphite occurs in form of flakes or lumps. Due to the superior electric and thermal conductivity, lubricity, high thermal shock resistance, chemical stability, and high performance of nuclear physics, Graphite can be used in battery electrodes, lubricants, pencils, neutron moderators in atomic reac-tors, and can also be used as the raw material of crucible and synthetic diamonds. In a diamond, the carbon atoms are arranged in a variation of a face-centered cubic crystal structure called a diamond lattice, in which one carbon atom is surrounded by four carbon atoms, the bonding force in every direction is equivalent (Figure 1.1). Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. Because they have the highest hardness and thermal conductivity, diamonds have been widely applied in cutting and polishing tools. The carbon atoms not only bond with each other by sp 3 hybrid to form a single bond, but also can form double and triple bonds with sp 2 and sp hybrid, respectively. Therefore, apart from the variety of carbon allotropes that exist in nature, scientists have successfully synthesized many carbon materials with different structures and properties.
eBook - PDF- Francis J. Clauss(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
Chapter 3 Graphite Graphite is the classic example of a low-friction solid. Its lubricating qualities are well known, and it is widely used to lubricate fine me-chanisms. A. OCCURRENCE AND PRODUCTION The term ' 'Graphite*' refers strictly to one of the two crystalline forms of carbon, the other crystalline form being diamond. The term carbon is customarily used in the industry to refer to amorphous (noncrystalline) carbon. There are two broad classification of Graphite: natural and synthetic. Natural Graphite is a mineral that occurs in veins or flakes with varying degrees of crystallinity, ranging from amorphous to highly crystalline, and in purity from 80 to 90% carbon. Synthetic, or manufactured, Graphite is made by heating petroleum coke to around 5000° F, and it has an aver-age purity of 98.5% carbon. It is not a specific material, however, but is a family of materials, each member of which is essentially pure carbon but differs from the other members in the degree of crystallinity, orienta-tion of the crystallites, pore structure, etc. Available grades range from the lowest cost, coarse-grained, relatively weak Graphites to fine-grained, strong, but expensive ones. Most Graphite is manufactured from pe-troleum coke, a refinery by-product, although any organic material that leaves a high carbon residue when heated can be used [la]. The final step in manufacturing Graphite is coverting the carbon to Graphite at 2600°-3000° C (4700°-5450° F). During this process the Graphite crystals that are randomly arranged in the baked carbon piece grow and rearrange in an ordered pattern of stacked parallel planes. Graph-itization is accompanied by an abrupt change in the physical properties, 42
eBook - PDFCarbon Nanomaterials
Synthesis, Structure, Properties and Applications
- Rakesh Behari Mathur, Bhanu Pratap Singh, Shailaja Pande(Authors)
- 2016(Publication Date)
- Taylor & Francis(Publisher)
The properties discussed next are either calculated or based on the actual properties of Graphite crystals closely approaching this ideal structure. As will be seen later in the text, a wide range of materials comes under the heading of carbon or Graphite and these materials often have properties that are much different from those of the ideal Graphite crystal. The material properties are sometimes confused with the nomenclature “carbon” or “Graphite.” Moreover, being a layered structure, properties of Graphite are highly anisotropic, that is, the properties of the material may vary considerably when measured along the in-plane “ab” directions or within the plane and in the “c” direction, that is, perpendicular to the planes. Such anisotropy, especially in electrical and thermal properties, can often be very useful in several applications. Valence band Conduction band D(ε) E c E g E(eV) 0 ~5.3 eV FIGURE 1.13 Theoretical sketch of the density of states of diamond. Zero energy is taken at the top of the valence or bonding band. (Adapted from I.L. Spain, Electronic transport: Properties of Graphite, carbons, and related materials, Chemistry and Physics of Carbon 16 (1981): 119–304.) 13 Introduction to Carbon and Carbon Nanomaterials 1.4.1 Electrical Properties of Graphite In electrical conductors such as metals, the attraction between the outer electrons and the nucleus of the atom is weak; the outer electrons can move readily and, since an electric cur- rent is essentially a flow of electrons, metals are good conductors of electricity. In electrical insulators (or dielectrics), electrons are strongly bonded to the nucleus and are not free to move. The atomic structure of Graphite is such that the highest filled valence band overlaps the lowest empty conduction band by approximately 40 meV; a few holes and electrons are always available to carry current. In pure Graphite the electron and hole densities are small and equal, and the carrier effective mass is low.
eBook - PDFMaterials Science of Polymers
Plastics, Rubber, Blends and Composites
- A. K. Haghi, Eduardo A. Castro, Sabu Thomas, P. M. Sivakumar, Andrew G. Mercader, A. K. Haghi, Eduardo A. Castro, Sabu Thomas, P. M. Sivakumar, Andrew G. Mercader(Authors)
- 2015(Publication Date)
- Apple Academic Press(Publisher)
CHAPTER 2 STRUCTURE OF GRAPHITIC CARBONS: A COMPREHENSIVE REVIEW HEINRICH BADENHORST 2.1 INTRODUCTION Graphite in its various forms is a very important industrial material it is utilized in a wide variety of specialized applications. These include high temperature uses where the oxidative reactivity of Graphite is very important, such as electric arc furnaces and nuclear reactors. Graphite intercalation compounds are utilized in lithium ion batteries or as fire retardant additives. These may also be exfoliated and pressed into foils for a variety of uses including fluid seals and heat management. Graphite and related carbon materials have been the subject of scientific inves-tigation for longer than a century. Despite this fact there is still a fundamental issue that remains, namely the supramolecular constitution of the various carbon materi-als [1, 2]. In particular it is unclear how individual crystallites of varying sizes are arranged and interlinked to form the complex microstructures and defects found in different bulk Graphite materials. Natural Graphite flakes are formed under high pressure and temperature condi-tions during the creation of metamorphosed siliceous or calcareous sediments [3]. Synthetic Graphite on the other hand is produced via a multistep, reimpregnation process resulting in very complex microstructures and porosity [4]. For both of these highly graphitic materials the layered structure of the ideal Graphite crystal is well established [5]. However, in order to compare materials for a specific applica-tion the number of exposed, reactive edge sites are of great importance. This active surface area (ASA) is critical for quantifying properties like oxida-tive reactivity and intercalation capacity. The ASA is directly linked to the manner in which crystalline regions within the material are arranged and interconnected. The
No longer available |Learn more- (Author)
- 2014(Publication Date)
- White Word Publications(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter-6 Graphene Graphene is an atomic-scale honeycomb lattice made of carbon atoms. Graphene is an allotrope of carbon, whose structure is one-atom-thick planar sheets of sp 2 -bonded carbon atoms that are densely packed in a honeycomb crystal lattice. The term graphene was coined as a combination of Graphite and the suffix -ene by Hanns-Peter Boehm, who described single-layer carbon foils in 1962. Graphene is most easily visualized as an atomic-scale chicken wire made of carbon atoms and their bonds. The crystalline or flake form of Graphite consists of many graphene sheets stacked together. ________________________ WORLD TECHNOLOGIES ________________________ The carbon-carbon bond length in graphene is about 0.142 nanometers. Graphene sheets stack to form Graphite with an interplanar spacing of 0.335 nm, which means that a stack of 3 million sheets would be only one millimeter thick. Graphene is the basic structural element of some carbon allotropes including Graphite, charcoal, carbon nanotubes and fullerenes. It can also be considered as an indefinitely large aromatic molecule, the limiting case of the family of flat polycyclic aromatic hydrocarbons. The Nobel Prize in Physics for 2010 was awarded to Andre Geim and Konstantin Novoselov for groundbreaking experiments regarding the two-dimensional material graphene. Description One definition given in a recent review on graphene is: Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional (2D) honeycomb lattice, and is a basic building block for graphitic materials of all other dimensionalities. It can be wrapped up into 0D fullerenes, rolled into 1D nanotubes or stacked into 3D Graphite. A previous definition is: A single carbon layer of the graphitic structure can be considered as the final member of the series naphthalene, anthracene, coronene, etc.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 6 Graphene Graphene is an atomic-scale honeycomb lattice made of carbon atoms. Graphene is an allotrope of carbon, whose structure is one-atom-thick planar sheets of sp 2 -bonded carbon atoms that are densely packed in a honeycomb crystal lattice. The term graphene was coined as a combination of Graphite and the suffix -ene by Hanns-Peter Boehm, who described single-layer carbon foils in 1962. Graphene is most easily visualized as an atomic-scale chicken wire made of carbon atoms and their bonds. The crystalline or flake form of Graphite consists of many graphene sheets stacked together. ________________________ WORLD TECHNOLOGIES ________________________ The carbon-carbon bond length in graphene is about 0.142 nanometers. Graphene sheets stack to form Graphite with an interplanar spacing of 0.335 nm, which means that a stack of 3 million sheets would be only one millimeter thick. Graphene is the basic structural element of some carbon allotropes including Graphite, charcoal, carbon nanotubes and fullerenes. It can also be considered as an indefinitely large aromatic molecule, the limiting case of the family of flat polycyclic aromatic hydrocarbons. The Nobel Prize in Physics for 2010 was awarded to Andre Geim and Konstantin Novoselov for groundbreaking experiments regarding the two-dimensional material graphene. Description One definition given in a recent review on graphene is: Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional (2D) honeycomb lattice, and is a basic building block for graphitic materials of all other dimensionalities. It can be wrapped up into 0D fullerenes, rolled into 1D nanotubes or stacked into 3D Graphite. A previous definition is: A single carbon layer of the graphitic structure can be considered as the final member of the series naphthalene, anthracene, coronene, etc.
eBook - PDF- Boris I. Kharisov, Oxana Vasilievna Kharissova, Ubaldo Ortiz-Mendez(Authors)
- 2012(Publication Date)
- CRC Press(Publisher)
The extracted 2D crystals become intrinsically stable by gentle crumpling in the third dimension; such 3D warping (observed on a lateral scale of ≈10 nm) leads to a gain in elastic energy but suppresses thermal vibrations (anomalously large in 2D), which above a certain temperature can minimize the total free energy (see Ref. [2] and references therein). Despite the fact that graphene was discovered recently, its structure, properties, and applications have already been generalized in a series of monographs 3–6 and reviews 7–10 (among which we note an excellent work of Mullen on graphenes as potential material for electronics 11 ). Various patents are dedicated to obtaining graphenes. 12–14 Among experimental works, we note a number of investiga-tions of Novoselov, 15–19 who precisely discovered this material. At present, the area of graphene is one of the most popular topics in physics and nanotechnology. 20 17.1 STRUCTURE AND PROPERTIES Graphene is a layer of carbon atoms, connected in a hexagonal 2D crystalline lattice, that is, a plane, consisting of hexagonal cells (Figure 17.1). It can be considered as one Graphite plane, separated from the voluminous crystal. Two atoms A and B are situated in an elementary cell of the crystal. Each one, at a displacement on the translation vectors, forms a sublattice from the atoms, equivalent to it, that is, crystal properties are nondependent on observation points, situated in the equivalent places of the crystal. The distance between the closest carbon atoms in graphene a 0 is 0.142 nm (Figure 17.2). An ideal graphene consists exclusively of hexagonal cells. The presence of penta- or heptagonal cells leads to various types of defects. 21 The appearance of pentagonal cells leads to a turning of the atomic plane to a cone. Examining 12 such defects simultaneously, the fullerene structure is formed. The presence of heptagonal cells leads to the formation of saddle-type distortions of the atomic plane.
- Francois Beguin, Elzbieta Frackowiak, Francois Beguin, Elzbieta Frackowiak(Authors)
- 2009(Publication Date)
- CRC Press(Publisher)
The deviation from unity is a consequence of the presence of edges. Each edge carbon atom takes two fluorine atoms in the reaction whereas the interior one takes one fluorine atom. The presence of excess fluorine concentration indicates the importance of the edges in the fluorination reaction in nanographene sheets. 6.5 SUMMARY Graphite, which is one of the allotropes in carbon, has unique features characterized by two-dimen-sionality and amphoteric nature. This is based on the 2D layered structure with the π -electronic structure extended in the constituent graphene sheets. The electronic structure of graphene, which is described in terms of the extrapolation of condensed polycyclic aromatic molecules to infinite size, 0 10 0.8 0 0.2 0.4 0.6 1 1.2 N s (g –1 ) ×10 19 (b) 0 4 – c orb (emu·g –1 ) ×10 –7 (a) F/C 0.8 0 0.2 0.4 0.6 1 1.2 F/C FIGURE 6.29 Orbital susceptibility χ orb (a) and localized spin concentration N s (b) for fluorinated ACFs with F/C = 0–1.2. Solid lines are guides for the eyes. (From Takai, K., et al., J. Phys. Soc. Jpn ., 70, 175, 2001. With permission.) Electronic Structures of Graphite and Related Materials 257 is given as zero-gap semiconductor with bonding π - and antibonding π * -electronic states touching to each other at the Fermi level. The stacking of graphene sheets in the AB fashion imparts bulk 3D Graphite, whose electronic structure is characterized with semimetal having small concentrations of electrons and holes as conduction carriers. The amphoteric nature of grapahene and Graphite is a consequence of electronic features of zero-gap semiconductor and semimetal. The two-dimensionality and amphoteric nature of Graphite play an important role in creating a large variety of Graphite-based materials, which are called GICs. Guest (intercalates) molecules of electron donors and acceptors are accommodated in the graphitic galleries through charge transfer between host Graphite and the guests.
eBook - PDFMaterials Science and Engineering, Volume II
Physiochemical Concepts, Properties, and Treatments
- Gennady E. Zaikov, A. K. Haghi, E. Klodzinska, Gennady E. Zaikov, A. K. Haghi, E. Klodzinska(Authors)
- 2016(Publication Date)
- Apple Academic Press(Publisher)
CHAPTER 13 RESEARCH METHODOLOGIES ON PHYSICOCHEMICAL PROPERTIES AND STRUCTURE OF GRAPHITIC CARBONS HEINRICH BADENHORST CONTENTS 13.1 Introduction .................................................................................. 290 13.2 Materials and Methods ................................................................. 291 13.3 Microstructure of Graphite .......................................................... 292 13.4 Conclusions .................................................................................. 319 Keywords .............................................................................................. 320 References ............................................................................................. 321 290 Materials Science and Engineering Vol 2 13.1 INTRODUCTION Graphite in its various forms is a very important industrial material, it is used in a wide variety of specialized applications. These include high tem-perature uses where the oxidative reactivity of Graphite is very important, such as electric arc furnaces and nuclear reactors. Graphite intercalation compounds are used in lithium ion batteries or as fire retardant additives. These may also be exfoliated and pressed into foils for a variety of uses including fluid seals and heat management. Graphite and related carbon materials has been the subject of scientific investigation for longer than a century. Despite this fact there is still a fundamental issue that remains, namely the supra-molecular constitution of the various carbon materials [1, 2]. In particular it is unclear how in-dividual crystallites of varying sizes are arranged and interlinked to form the complex microstructures and defects found in different bulk Graphite materials. Natural Graphite flakes are formed under high pressure and temperature conditions during the creation of metamorphosed siliceous or calcareous sediments [3].
eBook - PDFGraphene-Based Materials
Science and Technology
- Subbiah Alwarappan, Ashok Kumar(Authors)
- 2013(Publication Date)
- CRC Press(Publisher)
1 Chapter 1 Graphene: An Introduction 1.1 Graphene: History and Background The possibility of graphene’s existence or that of a two-dimensional (2D) allotrope of carbon has been theoretically studied for 60 years. Often, the term graphene was used to describe the properties of carbon allotropes [1–3]. However, after four decades it has been realized that graphene also provides an excellent condensed matter analogue of (2 + 1)-dimensional quantum electrodynamics [4–7], thereby exposing graphene to a thriving theoretical “toy” model [7]. Graphene was expected to be unstable due to the formation of curved structures such as soot, fullerenes, and nanotubes. Further, graphene was believed not to exist in its free state. Unexpectedly, in 2004, the prediction of graphene’s existence became true when freestanding graphene was discovered by Geim and Novoselov [8,9]. Moreover, the follow-up experi-ments demonstrated that its charge carriers were indeed massless Dirac fermions [10,11]. As a result of this phenom-enon, graphene is indeed the material of choice for numerous 2 ◾ Graphene-Based Materials: Science and Technology researchers. Geim and Novoselov shared the 2010 Nobel Prize in Physics for the discovery of graphene [12–14]. Graphene is considered the flat single layer of carbon atoms that are tightly packed into a honeycomb-like crystal-line lattice in a 2D fashion [8–11]. Further, graphene is often known as the “mother” or the basic building unit of all other carbon allotropes. For instance, graphene can be wrapped up to a zero-dimensional (0D) fullerene, rolled to resemble one-dimensional (1D) carbon nanotubes, or stacked to a three-dimensional (3D) Graphite (see Figure 1.1) [8–11]. To understand 2D graphene in detail, we briefly describe the 2D crystals [7]. A single atomic plane of graphene is Figure 1.1 Scheme showing graphene can be wrapped to 0D fuller-enes, wrapped to form 1D carbon nanotubes (CNTs), or stacked to form 3D Graphite.
eBook - PDF- Saeed Farrokhpay(Author)
- 2023(Publication Date)
- Arcler Press(Publisher)
INTRODUCTION TO CARBON MATERIALS 5 CONTENTS 5.1. Introduction .................................................................................... 122 5.2. The Graphite Family........................................................................ 126 5.3. The Diamond Class ......................................................................... 130 5.4. The Fullerene Family ....................................................................... 136 References ............................................................................................. 137 CHAPTER The Fundamentals of Materials Chemistry 122 5.1. INTRODUCTION Carbon (C) is an atomic number 6 element. The Periodic Table of Elements places it in Group 4. Carbon has three allotropes: diamond, Graphite, and fullerene (Figure 5.1). Graphite and diamond have densities of 3.52 and 2.26 grams per centimeter cube, correspondingly (Buckley and Edie, 1993; Dresselhaus and Avouris, 2001). Figure 5.1. There are three carbon allotropes which are: (a) Graphite, with the two hues illustrating the A and B layers in the AB stacking pattern; (b) diamond; (c) fullerene. There are pentagons and hexagons to be found. Sources: https://www.tf.uni-kiel.de/matwis/amat/iss/kap_4/advanced/t4_2_1. html#_dum_3; https://www.tf.uni-kiel.de/matwis/amat/iss/kap_4/illustr/i4_2_1. html; http://www.gcsescience.com/a38-buckminsterfullerene.htm. Introduction to Carbon Materials 123 5.1.1. Graphite The carbon atoms in Graphite are sp 2 hybridized, which means that each carbon has three covalent linkages (bonds) oriented to three distinct carbon atoms in a similar plane (Figure 5.1(a)). With the aid of the π-π interaction, the 4 th valence electron that isn’t engaged in the sp 2 hybridization of C is delocalized, resulting in in-plane metallic bonding. As a result, bonding inside the film is a covalent bonding and combination of metallic.
Index pages curate the most relevant extracts from our library of academic textbooks. They’ve been created using an in-house natural language model (NLM), each adding context and meaning to key research topics.
