Elemental carbon, chemistry

Dr. Franco Cataldo is adjunct professor of chemistry at the Tor Vergata University of Rome, Italy. He is also the R D manager in some private research organizations, including the Soc. Lupi Chemical Research Institute. Dr. Cataldo s research interests are mainly focused on elemental carbon chemistry with special emphasis on polyynes and fullerene chemistry other fields of interest are macromolecular chemistry and biochemistry, as well as astrochemistry. 

The La-Si binary system is very attractive in relation with elemental carbon chemistry. LaSi2 adopts the a-ThSi2 structure as shown in Fig. 7.8d and the coordination of Si in LaSi2 is a planner triangle. The structure is composed of sp -bonded silicon. LaSi2 is metallic and shows superconductivity with Tc = 2.5 K [55]. LaSi2 is a Zintl phase with delocalized electrons. If this sub-network is realized with all- p carbon without metal atoms, a new 3D carbon aUotrope will be obtained. The hypothetical 3D all-jp carbon phase is called hyper graphite [56, 57]. Metallic conduction is expected from theoretical band stracture calculations of the hypothetical structure. 

Chemists make compounds and strive to understand their reactions. My own interest lies in the chemistry of the compounds of the elements carbon and hydrogen, called hydrocarbons. These make up petroleum oil and natural gas and thus are in many ways essential for everyday life. They generate energy and heat our houses, fuel our cars and airplanes and are raw materials for most manmade materials ranging from plastics to pharmaceuticals. Many of the chemical reactions essential to hydrocarbons are catalyzed by acids and proceed through positive ion intermediates, called carbocations. 

Both antimony tribromide and antimony ttiiodide are prepared by reaction of the elements. Their chemistry is similar to that of SbCl in that they readily hydroly2e, form complex haUde ions, and form a wide variety of adducts with ethers, aldehydes, mercaptans, etc. They are soluble in carbon disulfide, acetone, and chloroform. There has been considerable interest in the compounds antimony bromide sulfide [14794-85-5] antimony iodide sulfide [13868-38-1] ISSb, and antimony iodide selenide [15513-79-8] with respect to their soHd-state properties, ferroelectricity, pyroelectricity, photoconduction, and dielectric polarization. 

Organic chemistry, then, is the study of carbon compounds. But why is carbon special Why, of the more than 30 million presently known chemical compounds, do more than 99% of them contain carbon The answers to these questions come from carbon s electronic structure and its consequent position in the periodic table (Figure 1.1). As a group 4A element, carbon can share four valence electrons and form four strong covalent bonds. Furthermore, carbon atoms can bond to one another, forming long chains and rings. Carbon, alone of all elements, is able to form an immense diversity of compounds, from the... 

Organic chemistry deals with the compounds of carbon, of which there are literally millions. More than 90% of all known compounds contain carbon atoms. There is a simple explanation for this remarkable fact. Carbon atoms bond to one another to a far greater extent than do atoms of any other element. Carbon atoms may link together to form chains or rings. 

By this term we understand bonds between heteroelements in the sense of classical organic chemistry, i.e. bonds which do not include the element carbon. 

That branch of chemistry which deals with the compounds of the element carbon the simpler carbon-containing compounds (such as calcium carbonate) are usually classed with inorganic chemistry and an alternative definition of organic chemistry is the chemistry of the hydrocarbons and their compounds. 

In the study of the origin of life on earth, the element carbon is essential. Carbon is a required component of the fundamental molecules of life amino acids, bases, and sugars. In addition, a large variety of carbon compounds is necessary in the complex biochemical cycles of living organisms. The physical and chemical nature and geometry of the carbon atom make it well suited to form the vast array of molecules involved in the chemistry of life. 

Abstract The past two decades have profoundly changed the view that we have of elemental carbon. The discovery of the fullerenes, spherically-shaped carbon molecules, has permanently altered the dogma that carbon can only exist in its two stable natural allotropes, graphite and diamond. The preparation of molecular and polymeric acetylenic carbon allotropes, as well as carbon-rich nanometer-sized structures, has opened up new avenues in fundamental and technological research at the interface of chemistry and the materials sciences. This article outlines some fascinating perspectives for the organic synthesis of carbon allotropes and their chemistry. Cyclo[n]carbons are the first rationally designed molecular carbon allotropes, and... 

In the right part of the Table hydrides having covalent characteristics are observed. For the elements of the last groups several covalent hydrogen compounds are known numerous compounds are given by B, C, Si, Ge, N, P, O, S, Se. In the usual ambient conditions, as it is well-known, the carbon chemistry is especially rich of hydrides (that is of several series of hydrocarbons). In this class of compounds more or less complex molecules and structures are found the catenation (chainforming) tendency is a characteristic shown by several elements in this portion of the Periodic Table. 

A comprehensive book series which encompasses the complete coverage of carbon materials and carbon-rich molecules from elemental carbon dust in the interstellar medium to the most specialized industrial applications of elemental carbon and its derivatives. A great emphasis is placed on the most advanced and promising applications ranging from electronics to medicinal chemistry. The aim is to offer the reader a book series which not only consists of self-sufficient reference works, but one which stimulates further research and enthusiasm. 

Molecules are assembled from atoms of the chemical elements. Many elements form multiple chemical bonds in molecules. Among the elements, carbon is unique in its ability to form chains of atoms endlessly long. The structural chemistry of carbon is the richest of that for all the elements. 

My point is that chemistry imitates life in terms of the richness added by diversity. Up to this point, our experience has been pretty much at the meat-and-potatoes level, with focus on only two elements carbon and hydrogen. We can add interest by adding diversity in terms of additional elements. 1 begin doing that here. 

Today, carbon chemistry is more closely related to organic and hydrocarbon chemistry than to the elemental aUotropes of carbon. Over the past century organic and hydrocarbon chemistry has opened up vast areas of research and development leading to new commercial processes and products. 

The element carbon (symbol C) is almost always found in nature covalently bonded to other carbon atoms or to a variety of other elements (most commonly H, O, and N). Due to the presence of carbon-containing compounds in all living things, the chemistry of carbon compounds is known as organic chemistry. Most high explosives are organic compounds. TNT (trinitrotoluene), for example, consists of C, H, N, and O atoms, with a molecular formula of C yH 5N P e. We will encounter other organic compounds in our study of fuels and binders in pyrotechnic mixtures. 

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