Allotropes of Carbon
Allotropes of carbon are different forms of carbon that exist in the same physical state but have different chemical structures. Some well-known allotropes of carbon include diamond, graphite, and graphene. Each allotrope has unique properties and uses, such as diamond's hardness, graphite's conductivity, and graphene's strength and flexibility. These allotropes play a significant role in various industrial and technological applications.
7 Key excerpts on "Allotropes of Carbon"
eBook - ePubNanotechnology
Device Design and Applications
- Shilpi Birla, Neha Singh, Neeraj Kumar Shukla, Shilpi Birla, Neha Singh, Neeraj Kumar Shukla(Authors)
- 2022(Publication Date)
- CRC Press(Publisher)
...14 Carbon Allotropes-Based Nanodevices Graphene in Biomedical Applications Sugandha Singhal, and Meenal Gupta University School of Basic & Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka Sector 16C, New Delhi-110078, India Md. Sabir Alam NIMS Institute of Pharmacy, NIMS University, NH-11C, Delhi-Jaipur Expy, Sobha Nagar, Jaipur, Rajasthan, India Md. Noushad Javed Department of Pharmacy, School of Medical and Allied Sciences, KR Mangalam University, Gurugram, India Jamilur R. Ansari Faculty of Physical Sciences, PDM University, Sector 3A, Bahadurgarh-124507, Haryana, India DOI: 10.1201/9781003220350-14 14.1 Introduction Carbon is a nonmetallic, tetravalent element that is also a building block of life on earth. The unique property of self-binding and binding other elements results in the formation of structurally diverse compounds possessing varied physical and chemical properties. The applicative importance is well observed in versatile technical drug applications (Figure 14.1). Figure 14.1 Different dimensional Allotropes of Carbon. Fullerenes, carbon dot and graphene dot are examples of (0D). SWCNT, MWCNTs and SWCNHs are examples of (1D). Graphene-hCNTs hybrid, Schwarzite and multi-layered graphitic sheets are examples of (2D). Graphite and diamond are examples of (3D). Material scientists have succeeded in tailoring the structural and functional properties of existing materials to create new and modified versions by altering synthetic routes [ 1 ]. The two naturally occurring carbon allotropes are graphite with sp 2 hybridized and diamond with sp 3 hybridized carbon networks. Graphite is soft, ductile and conductive, whereas diamond is hard and insulating; thus, they show unique opposing properties. In 1985, the first synthetic carbon allotrope, zero dimension (0D) fullerene was discovered by Kroto et al...
eBook - ePubCarbon Nanotubes
Properties and Applications
- Michael J. O'Connell(Author)
- 2018(Publication Date)
- CRC Press(Publisher)
...In contrast to diamond, each carbon atom in a graphite sheet is bonded to only three other atoms; electrons can move freely from an unhybridized p orbital to another, forming an endless delocalized πbond network that gives rise to the electrical conductivity. Figure 1.1 The three Allotropes of Carbon. (From http://smalley.rice.edu/smalley.cfm?doc_id=4866.) Buckminsterfullerenes, or fullerenes, are the third allotrope of carbon and consist of a family of spheroidal or cylindrical molecules with all the carbon atoms sp 2 hybridized. The tubular form of the fullerenes, nanotubes, will be the subject of this book, and a detailed description of their history, properties, and challenges will be given in the next section. 1.2 History Fullerenes were discovered in 1985 by Rick Smalley and coworkers. 2 C 60 was the first fullerene to be discovered. C 60, or “bucky ball,” is a soccer ball (icosahedral)-shaped molecule with 60 carbon atoms bonded together in pentagons and hexagons. The carbon atoms are sp 2 hybridized, but in contrast to graphite, they are not arranged on a plane. The geometry of C 60 strains the bonds of the sp 2 hybridized carbon atoms, creating new properties for C 60. Graphite is a semimetal, whereas C 60 is a semiconductor. The discovery of C 60 was, like many other scientific breakthroughs, an accident. It started because Kroto was interested in interstellar dust, the long-chain polyynes formed by red giant stars. Smalley and Curl developed a technique to analyze atom clusters produced by laser vaporization with time-of-flight mass spectrometry, which caught Kroto’s attention. When they used a graphite target, they could produce and analyze the long chain polyynes (Figure 1.2a). In September of 1985, the collaborators experimented with the carbon plasma, confirming the formation of polyynes. They observed two mysterious peaks at mass 720 and, to a lesser extent, 840, corresponding to 60 and 70 carbon atoms, respectively (Figure 1.2b)...
eBook - ePub- Greg T. Hermanson(Author)
- 2013(Publication Date)
- Academic Press(Publisher)
...Chapter 16 Buckyballs, Fullerenes, and Carbon Nanotubes 1 Buckyballs and Fullerenes 1.1 Properties of Fullerenes Carbon is an incredible element that is able to form structures having highly diverse properties depending on its bonding patterns and 3-dimensional organization. Natural Allotropes of Carbon include diamond, graphite, amorphous carbon, and several other known forms (Figure 16.1). Depending on the bond structure and atomic orientation that carbon takes on within the structure of an allotrope, the resultant characteristics can range from the hardest-known abrasive mineral, diamond, to the extremely soft graphite, which is used as a lubricant. Figure 16.1 Three major Allotropes of Carbon. In 1985, the story of carbon allotropes took a dramatic turn with the discovery of C 60, which resulted in a new type of carbon structure, called fullerenes (Kroto et al., 1985). This discovery earned the 1996 Nobel Prize in chemistry for Harold Kroto, Robert Curl, and Richard Smalley. Buckminsterfullerene (named after Buckminster Fuller for his geodesic dome architectural design) is a spherical cage of carbon having 60 atoms forming a truncated icosahedron of average diameter 0.72 nm, which contains 12 pentagons and 20 hexagons of bonded carbon (Figure 16.2). The shape is exactly the same as a modern soccer ball, with the pentagon and hexagon configurations clearly outlined on its surface. Figure 16.2 The structure of a C 60 fullerene, also called a Buckyball. There now are known to be a whole family of caged carbon structures having various numbers of carbon atoms, including C 30, C 50, C 70, C 72, C 76, C 84, and the huge C 540...
eBook - ePub- Chris Binns(Author)
- 2021(Publication Date)
- Wiley(Publisher)
...3 Carbon Nanostructures : Bucky Balls and Nanotubes This chapter focuses on nanostructures produced by carbon. It may seem strange to devote a chapter to a single element, but there is such a plethora of nanostructures composed of carbon that it is easy to justify several books, never mind a chapter on them. Here we will pass lightly over the subject and discuss how and why these structures form and their basic properties. Some technological applications will also be presented, but carbon nanostructures are ubiquitous in nanotechnology and references to them can be found throughout the rest of this book. 3.1 Why Carbon? Carbon is a light simple element, its atoms containing just six electrons, two of them being core (1 s) electrons and the remaining four (2 sp) available for bonding with other atoms. It is the slightly schizophrenic nature of the chemical bonding by these four that naturally gives carbon a diversity of forms. The details of the environment in which the atoms come together (pressure, temperature etc.) determine the types of bonds. For example, we are familiar with the two very different bulk forms (allotropes) of carbon, that is, graphite, and diamond that result from different types of bonds. The bonding in diamond and graphite and why they adopt their particular crystal structures are illustrated in Figure 3.1. The diagrams on the left show the charge distribution associated with the four bonding electrons for the two crystal structures. It is important to realize that these have no meaning out of the context of bonding to other atoms (see advanced reading Box 3.1). They are the charge distributions that would be found if we suddenly plucked a carbon atom out of its crystal and somehow kept the electronic charge distribution associated with the atom frozen...
eBook - ePubNanotechnology in Textiles
Theory and Application
- Rajesh Mishra, Jiri Militky(Authors)
- 2018(Publication Date)
- Woodhead Publishing(Publisher)
...3 Carbon-based nanomaterials Rajesh Mishra; Jiri Militky Department of Material Engineering, Faculty of Textile Engineering, Technical University of Liberec, Liberec, Czech Republic Abstract Carbon is an extremely versatile material exhibiting a large number of unique properties. It exists as several different allotropes that range from 1-D to 3-D structures that are used in numerous applications. The characterization and applications of single carbon allotropes are extremely large, and many of the fundamental properties of the various allotropes have been extensively characterized. Carbon nanoparticles and nanotubes are extensively studied in recent times for their multifunctional applications. The current chapter discusses various carbon-based nanomaterials and their specific characteristics. Selected applications are also described in some detail. Keywords Nanoporous carbon; Single-walled carbon nanotube (SWCNT); Multiwalled carbon nanotube (MWCNT); Fullerenes; Graphene 3.1 Introduction Carbon is very unique material with many allotropes having quite different behavior from amorphous (charcoal and carbon black) to crystalline (diamond and graphite) structures. The properties of carbon structures vary uniquely with allotrope type. For example, there are huge differences between diamond and graphite. Diamond is highly transparent and very hard (microhardness of 100 GPa), with highest thermal conductivity but extremely low electric conductivity. Graphite is opaque and black, relatively soft, and a very good electric conductor. Nanocarbon materials play a critical role in the development of new or improved technologies and devices for sustainable production and use of renewable energy...
eBook - ePubNanocarbon and Its Composites
Preparation, Properties and Applications
- Anish Khan, Mohammad Jawaid, Abdullah M. Asiri, Inamuddin, Anish Khan, Mohammad Jawaid, Dr. Inamuddin, Abdullah M. Ahmed Asiri(Authors)
- 2018(Publication Date)
- Woodhead Publishing(Publisher)
...However, a marked and rapid growth of interest has been shown by the scientific and engineering communities in the organic [7, 8] and carbon-based nanomaterials. Over the last two decades, carbonaceous nanofillers such as graphite, diamond, fullerene, and CNTs have established widespread research. They are challenging due to their superior behaviors and interesting applications over other materials [9]. Among these engineered three-dimensional (3D) CNT and 2D graphene honeycomb lattice structure nanomaterials is one of the most promising functional materials, utilized in various fields due to its positive features including the properties of thermal, electrical, and mechanical strength as well as elasticity [2, 10]. CNTs and fullerenes are the Allotropes of Carbon characterized by a hollow structure and extraordinary thermal, electrical, and mechanical properties. Spherical fullerenes are also called buckyballs whereas cylindrical ones are known as nanotubes. The walls of these structures consist of a single layer of carbon atoms called graphene [11]. Although carbon is ubiquitous in nature, CNTs are a man-made form of carbon [12]. Among them, CNT possess better structural and fascinating properties which attracted it utilization and opened up a broad range of possible studies and functional applications [13, 14]. The development and characterization of inorganic hybrids consisting of metal oxide (MO) and CNTs are gaining attention, in terms of superior electronic, optical, and mechanical properties [9, 15, 16]. The discovery of CNTs perhaps contributed to the nanotechnology revolution, owing to their superior thermal, physical, optical, and electrical properties as well as a remarkably high thermal conductivity [17]. A Japanese scientist Iijima is known for his discovery of CNTs. However, according to Monthioux and Kuznetsov [18], CNTs were discovered much earlier than the 1990s...
eBook - ePubNanomaterials and Nanocomposites
Synthesis, Properties, Characterization Techniques, and Applications
- Rajendra Kumar Goyal(Author)
- 2017(Publication Date)
- CRC Press(Publisher)
...6 Synthesis, Properties, and Applications of Carbon Nanotubes Carbon nanotubes (CNTs) are unique tubular structures of carbon with a few nanometer diameter and large aspect ratio. The nanotubes may consist of one to few tens of concentric shells of carbons with adjacent shells separation of ∼ 0.34 nm. CNTs made of one hollow seamless graphitic shell are called single wall nanotubes (SWNTs) and have diameters typically 0.6–3 nm. CNTs made of two or more seamless concentric shells are called multi-walled nanotubes (MWNTs). Their high Young’s modulus and tensile strength makes them preferable reinforcement for composites based on polymer, metal, and ceramic matrices with improved thermal, mechanical, and electrical properties. The CNTs can be metallic or semiconducting depending on their structure. Due to their unique electronic properties, CNTs find application in electronic devices such as field effect transistors (FETs), single electron transistors, and rectifying diodes. The huge surface to volume ratio makes them very useful as hydrogen storage materials. This chapter is intended to summarize some of the important synthesis methods including arc discharge, laser ablation, catalytic growth, or chemical vapor decomposition (CVD), and high-pressure carbon monoxide (HiPCO) decomposition. Moreover, the optical, electrical, mechanical and thermal properties, and applications of CNTs are also discussed. 6.1 Introduction In 1991, for the first time Iijima [ 1 ] investigated multiwalled carbon nanotubes (MWNTs) with adjacent shell separation of ∼ 0.34 nm. After 2 years, Bethune et al. [ 2 ] and Iijima et al. [ 3 ] reported synthesis of single-walled carbon nanotubes (SWNTs). Nowadays, MWNTs and SWNTs are synthesized mainly by four techniques such as arc discharge, laser ablation, catalytic growth, and HiPCO decomposition. There are several other methods for the synthesis of CNTs but those methods are not discussed here...
