CARBON AND ITS COMPOUNDS
CARBON IS A NON-METAL
SYMBOL :C
ATOMIC No : 6
VALENCY : 4
Group No: 14
It occurs in elemental form as well as in
combined form such as
CARBONATES, COAL, PETROLEUM AND CO2
The compounds of carbon are called ORGANIC
COMPOUNDS.
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Carbon is one of the least abundant elements in the
Earth's crust, but the fourth most abundant element in
the universe by mass after hydrogen, helium, and
oxygen.
It is present in all known lifeforms, and in the human
body carbon is the second most abundant element by
mass (about 18.5%) after oxygen
This abundance, together with the unique diversity of
organic compounds and their unusual polymer-forming
ability at the temperatures commonly encountered on
Earth, make this element the chemical basis of all
known life.
Allotropy & Allotropes
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Allotropes are different physical forms of the
same element which have same chemical
properties but different physical properties,
and the phenomenon is known as Allotropy.
Carbon exhibit allotropy.
The three relatively well-known allotropes of
carbon are amorphous carbon, (charcoal,
lampblack (soot) and activated carbon )
graphite, and diamond.
Allotropes of carbon
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There are several allotropes of carbon of which the best known
are graphite, diamond, and amorphous carbon.
The physical properties of carbon vary widely with the allotropic
form. For example, diamond is highly transparent, while graphite
is opaque and black.
Diamond is among the hardest materials known, while graphite
is soft enough to form a streak on paper (hence its name, from
the Greek word "to write").
Diamond has a very low electrical conductivity, while graphite is
a very good conductor.
Under normal conditions, diamond has the highest thermal
conductivity of all known materials.
All the allotropic forms are solids under normal conditions but
graphite is the most thermodynamically stable.
Appearance
Clear (diamond), black (graphite)
Graphite ore
Raw diamond crystal
Structure of Diamond and Graphite
Allotropes of Carbon - Fullerenes

In 1985 the carbon structure
family was completed by a
new modification of pure
carbon. With the discovery of
the fullerenes by Curl,
Smalley and Kroto [1] and
additionally with the possibility
for the production of
fullerenes in large amounts
shown by Krätschmer and
Huffman [2] in 1990 the
scientific competition in
experimental and theoretical
research was started.
BONDING IN CARBON COMPOUNDS
THE COVELENT BOND
A bond formed between two atoms by
mutual sharing of electrons between them so
as to complete their octet is known as covalent
bond.
A carbon atom has 4 electrons in its valence
shell, so it needs 4 electrons to attain stable
electronic configuration of nearest noble gas.So
carbon forms bond by sharing its valence
electron with any other atom.
C
Formation of methane molecule
H
C
+4
H
--
H
C
H
H
Structure of Methane CH4
Tetravalent Nature

Due to its tetravalent nature carbon always form
covalent bonds by sharing electrons with one, two,
three or four carbon atoms or atoms of other
elements or groups of atoms as discussed earlier.
The tetra covalency of carbon atom allows
it to combine easily with other carbon atoms to form
a stable chain like structure i.e., exhibiting the
property of catenation. Catenation usually occurs
because the atom-to-atom covalent bond is quite
strong. The chains having different chain lengths
and structures and combines with different elements
it leads to the formation of a large number of
compounds
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)
Molecular Compounds
The simplest molecule is H2:
Increased electron density
draws nuclei together
The pair of shared electrons constitutes a
covalent bond.
Lewis Structures
• Covalent bonding in a molecule is represented by a Lewis structure.
• A valid Lewis structure should have an octet
for each atom except hydrogen.
Nonbonding electrons
Cl
Cl


or

Bonding
electrons

Cl
Cl
 









Cl
+ Cl



Cl2:




H +  H  H H or H H
H2:
Lewis Structures
Draw Lewis structures for:
CH4:



H N H

H
H

H C
H

H

or
or
or
or



H O
H


NH3:


H2O:
H F

HF:


H F


H O
H


H N H
H
H
H C H
H
Double and Triple Bonds
• Atoms can share four electrons to form a
double bond or six electrons to form a triple
bond.


N2:
N N

O
=O



O2:
• The number of electron pairs is the
bond order.
Unique properties of Carbon atom
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Carbon has the ability to form very long chains of
interconnecting C-C bonds. This property is called
catenation.
Carbon-carbon bonds are strong, and stable. This
property allows carbon to form an almost infinite
number of compounds; in fact, there are more
known carbon-containing compounds than all the
compounds of the other chemical elements
combined except those of hydrogen (because
almost all organic compounds contain hydrogen
too).
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The simplest form of an organic molecule is the
hydrocarbon—a large family of organic molecules
that are composed of hydrogen atoms bonded to a
chain of carbon atoms.
Formation of covalent bond in carbon
compounds
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Formation of Strong C-C Covalent Bonds
The single bond formed between the carbon atoms
is strong. This results in the formation of stable
compounds. Carbon atom can also form stable
bonds with other atoms like H, Cl, Br, O, etc.
Formation of C-C Multiple Bonds
Due to its small size the carbon atom can also form
multiple bonds i.e., double and triple bonds with not
only carbon but with atoms of other elements like
oxygen, nitrogen, etc. The formation of these
multiple bonds gives rise to a variety in the carbon
compounds.
Formation of C-C Multiple Bonds
Types and number of bonds
n
g
l
e
a
n
d
o
n
e
d
o
u
b
l
e
b
o
n
d
.
T
r
i
g
o
n
a
l
g
e
o
m
e
t
r
y
(
s
p
Linked to four atoms with four single bonds. Tetrahedral
3
geometry (sp hybridisation)
Linked to three atoms with two single and one double bond.
2
Trigonal geometry (sp hybridisation)
Linked to two atoms with one single and one triple bond.
Linear geometry (sp hybridisation)
2
h
y
b
r
i
d
i
s
a
Structure
Homologous series
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All organic compounds are made up of a
progressively building chain of carbon atoms with a
number of compounds having the same functional
groups.
Such a series of similarly constituted compounds
are called a homologous series.
Members of a homologous group are similar in
structure and display similar chemical
characteristics.
The two consecutive members of the series differ in
their molecular formula by a 'CH2' group.
Some important characteristics of the
homologous series
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All the members conform to a general molecular
formula and have a similar functional group.
Each consecutive member differs in the molecular
formula by a unit of 'CH2'.
All the members of the series exhibit similar
properties, but the extent of the reactions vary with
increasing relative molecular mass.
The physical properties, such as solubility, melting
point, boiling point, specific gravity etc. show a
gradual change with the increase in their relative
molecular masses
Homologous series of Alkanes
IUPAC Names
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With the large growth of carbon compounds, it was necessary to name
these compounds in a more systematic way. A committee called the
'International Union for Pure and Applied Chemistry' (IUPAC) put forward
a system of giving proper scientific names to carbon based compounds.
The names derived by their rules are the names followed all over the
world and in short are called IUPAC names.
In this system the name of a carbon compound has three main parts as
mentioned below:
Wood Root
This denotes the number of carbon atoms present in a given molecule.
For e.g., C1-Meth, C2- Eth, C3 - Prop, C4- But.
Suffix
The suffix denotes the type of bonds or the functional group present in
the carbon chain, e.g.
Type of bondFunctional group'ane' (single bond)'ol' for alcohols (OH)'ene' (double bond)'al' for aldehydes (-CHO)'yne' (triple bond)'oic
acid' for carboxylic acid (-COOH)
IUPAC Names
Functional group
Secondary
suffix
Functional group
Secondary
suffix
Alcohols (-OH)
-ol
Aldehydes (-CHO)
-al
Ketones (>C=O)
-one
Carboxylic acids (COOH)
-oic acid
Amines (-NH2 )
-amine
Acid amides (-CONH2 )
-amide
Acid chlorides (COCL)
-oyl chloride
Esters (-COOR)
-oate
-nitrite
Thioalcohols (-SH)
-thiol
=
Nitrites (-C N)
Nomenclature of compounds having
polyfunctional groups
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When an organic compound contains two or more functional
groups, one group is called the principal functional group while
the others are called the secondary functional groups and are
treated as substituents: The order of preference for principal
group is: Carboxylic acid > acid anhydrides > esters > acid
halides > amides > nitrites > aldehydes > ketone > alcohols >
amines > double bond > triple bond
When the functional groups act as substituents, they ar named
as:
Functional groupPrefixFunctional groupPrefixCOOHCarboxy-CHOFormyl-COORAlkoxy cabonyl or
Carbalkoxy>COOxo or Kelo-COCLChloroformyl-OHHydroxyCONH2 Carbamoyl-SHMecaplo-CNCyano-NH2 AminoORAkoxy=NHImino
Functional
group
Prefix
Functional
group
Prefix
- COOH
Carboxy
-CHO
Formyl
-COOR
Alkoxy cabonyl or
Carbalkoxy
>CO
Oxo or
Kelo
-COCL
Chloroformyl
-OH
Hydroxy
-CONH2
Carbamoyl
-SH
Mecaplo
-CN
Cyano
-NH2
Amino
-OR
Akoxy
=NH
Imino
-X
Halo
-NO2
Nitro
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For e.g., the following compound can be
named as:

Word root: But (C4)
Prefix: 3, chloro
Suffix: -ol
Name: 3-chloro butanol
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Trivial Names, IUPAC Names and Molecular
Formula of some Organic Compound
Trivial name
IUPAC names
Methane
Methane
Ethane
Ethane
Ethylene
Ethene
Acetylene
Ethyne
Formaldehyde
Methanal
Acetaldehyde
Ethanal
Formic acid
Methanoic acid
Acetic acid
Ethanoic acid
Formula
ABOUT CARBON
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Carbon is the sixth most abundant element in the
cosmos, yet its abundance in the earth's crust does
not even make it among the top ten elements on our
planet. There are more known chemical compounds
of carbon than any other element except for oxygen
and hydrogen. Carbon composes compounds with
diverse properties such as graphite and diamond, as
well as the recently discovered Buck Minster
Fullerenes, or buckyballs. Carbon plays a critical role
on Earth as the "stuff" that Life is made from. Every
living cell, plant or animal contains carbon. Even in its
pure, elemental form carbon is very versatile.
Carbon : Here…there…and everywhere…
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Graphite is found in large deposits in Sri Lanka,
Malagasy Republic, the former USSR, South Korea,
Mexico, and Czechoslovakia. Economic deposits at Val
Chisone (Italy). Small hexagonal crystals in marble at
Ogdensburg, New Jersey (USA) and in gneiss at
Edison, New Jersey (USA).
Natural: It is formed in high-grade metamorphic rocks
as a final product of the carbonisation of organic
materials. It is probably also a primary magmatic
substance in some pegmatite's and hydrothermal
veins.
Synthetic: Coke is a graphite product that is about 94%
carbon. It is produced by heating soft coal in an oven
that has no access to air. Most of the impurities
sublime off, leaving fairly pure carbon.
Carbon : Here…there…and everywhere…
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Graphite is found in large deposits in Sri Lanka,
Malagasy Republic, the former USSR, South Korea,
Mexico, and Czechoslovakia. Economic deposits at Val
Chisone (Italy). Small hexagonal crystals in marble at
Ogdensburg, New Jersey (USA) and in gneiss at
Edison, New Jersey (USA).
Natural: It is formed in high-grade metamorphic rocks
as a final product of the carbonisation of organic
materials. It is probably also a primary magmatic
substance in some pegmatite's and hydrothermal
veins.
Synthetic: Coke is a graphite product that is about 94%
carbon. It is produced by heating soft coal in an oven
that has no access to air. Most of the impurities
sublime off, leaving fairly pure carbon.
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Diamond: Splendid crystals of Diamond occur in the kimberlites of
South Africa, Yakutia (former USSR), Murfreesboro, Arkansas (USA),
Brazil, Zaire, Sierra Leone and Ghana. Small, nongem-quality
crystals are found in Brazil, Venezuela, Zaire and other countries.
Natural: It is formed in ultramafic rocks, especially kimberlite breccias,
and in detrital sedimentary deposits derived from them, in river and
marine placers. A rare form of hexagonal "diamond" known as
Lonsdaleite is found in certain meteorites, such as those from Canyon
Diablo, (USA).
Synthetic: Most industrial-grade diamonds are produced, with the aid
of catalysts, by subjecting high-grade graphite to extremely high
temperature and mechanical pressure over a period of several days
or weeks. Dr. Guy Suits of the General Electric Company synthesized
the first man-made diamonds in 1957.
INTRODUCTION

In 1985 the carbon structure
family was completed by a
new modification of pure
carbon. With the discovery of
the fullerenes by Curl,
Smalley and Kroto [1] and
additionally with the possibility
for the production of
fullerenes in large amounts
shown by Krätschmer and
Huffman [2] in 1990 the
scientific competition in
experimental and theoretical
research was started.

Fullerenes are polyeders build up by n three times
coordinated carbon atoms with 12 pentagons and
(n) hexagons, were the minimum for n equal 20 is.
Fullerenes fulfil the EULER's theorem, were a
polyeder build up from pentagons and hexagons
has to contain exact 12 pentagons, to build a closed
structure. Following this rule, the dodekaeder with
20 carbon atoms is the smallest possible fullerene.
Actual the smallest fullerene is the C60, because
important for the stability of the structure is, that no
pentagons are side by side. This is described by the
Isolated Pentagon Rule (IPR). If two pentagons are
annulled, the tension of the binding is increasing
and the structure is not anymore energetic stable.
CHEMICAL AND PHYSICAL PROPERSTIES
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The carbon atoms in fullerenes are spm
(m=2...3). The free valence electrons on the cage
building a strong localized π-electron system.
This π-electron system influences chemical
reactions of the fullerenes. In chemical reactions
fullerenes are not reacting aromatic ("super
benzene"), they show aliphatic behaviour.
Good solvents for fullerenes are CS2, odichlorobenzene, toluene and xylene [7, 8, 9].
Fullerenes are insoluble in water and stabile at
air. Thin layers of fullerenes are coloured from
yellow to yellow-green.
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Because of ππ*-electron transitions solutions of
fullerenes are coloured [10]:
- C60 purple/violet red
- C70 brick-red
- C76 light yellow-green
- C2v-C78 maroon, D3-C78 golden,
- C84 brown and
- C86 olive-green.
By heating fullerenes without air up to 1500 °C they
transform to graphite.
These fullerenes were discovered in 1985 and after
solid phase research they have been found in
geological material and in the flames of candles.
SPECIES OF FULLERENES

Following species of fullerenes are known:
- fullerenes
- fullerites [11]
- fullerides [11]
- endohedral fullerenes
- exohedral fullerenes
- heterofullerenes [12, 13]
- metcars.

Professors Curl and Smalley of the United States
and Professor Sir Kroto from the United Kingdom
were awarded the Nobel Prize in chemistry in
1996 for the discovery of the buckyball.
The discovery in 1985 of
buckminsterfullerene opened a new era
for the chemistry of carbon and for
novel materials. The Japanese Sumi
Ijima discovered Nanotubes in 1991.
The Nanotubes synthesised in the
laboratory showed remarkable
mechanic properties as well as thermal
conductivity and resistance to flame.
These Nanotubes consist of layers of
graphite in the form of cylinders and
often closed at both ends. They can
exist as single and multi walled
Nanotubes. Normally their diameter is
only a few nanometres and their length
a millimetre
*Nanotubes (a) armchair (b) zag zag
(c) chiral

Nanotubes can be obtained by mixing the soot of
Nanotubes of carbon in water and surfactant. This viscous
solution is rotated in a substance capable of aggregating
the Nanotubes. A liquid is then injected to aid the formation
of a rectangular section, which rolls itself into a cylinder
and thus forms carbon Nanotubes. Another method is to
decompose methane with a catalyst. The enlargement of
the basal plans of graphite on existing surfaces causes
Nanotubes without extremities to extend and
l’epaissement the tubes. These tubes are semi-conductors
or metallic conductors depending on small variations of
their angle of curvature or diameter. This angle defines the
type of Nanotubes (armchair, zig zag or chiral) and it is
determined by the way the layers of graphite wrap around
and interact with themselves. Their properties of
conduction depend on their diameter and the way they are
helicoidal. Nanotubes are tested with scanning tunnelling
microscopy at low temperatures, and a measure of their
electronic and physical structure. Even with Nanotubes
made by different methods, the results are complimentary
and confirm that the conduction is only in one dimension.
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Furthermore, fullerenes are very important in
pharmaceutical applications. Wudl synthesised a
derivative of a fullerene which is soluble in water. It
seems to inhibit the activity of HIV and could be used in
a medicine for the treatment of AIDS. Nanotechnology
is thus a domain of central importance, at the forefront
of chemistry, physics, engineering and materials
science. Nanotechnology find ways of manipulating
atoms and molecules in an effort to construct new
materials and different molecular stratagems.
In conclusion, carbon is truly important for chemistry
and for life. It is essential that we continue to study the
chemistry of carbon to increase understanding of
ourselves and our environment and to improve the
quality of life.