Carbon: An Elemental Nexus in the Fabric of Life and Materials

Food, clothes, medicines, books, or many other things are all based on this versatile element carbon. In addition, all living structures are carbon based.  Carbon is available in nature, The importance of carbon and its compounds in nature is immense.

About Carbon and its compounds

• Atomic Number: Carbon is a chemical element with the atomic number 6 and the symbol C.
• Covalent Bonding: Bonds which are formed by the sharing of an electron pair between two atoms are known as covalent bonds. 
  • Weak Intermolecular Force: Covalently bonded molecules are seen to have strong bonds within the molecule, but intermolecular forces are weak. 
  • This gives rise to the low melting and boiling points of these compounds. 
  • Covalent compounds such as Carbon are generally poor conductors of electricity.
  • Reason being that the bonding in the carbon and its compounds does not give rise to any ions.

Carbon’s Tetravalency and Covalent Bonds: A Comparative Analysis

• To achieve the electronic configuration of the nearest noble gas, “He” , if the carbon atom loses four of its valence electrons, a huge amount of energy is involved. 
• C4+ ions, hence formed, will be highly unstable due to the presence of six protons and two electrons.
• If the carbon atom gains four electrons to achieve the nearest electronic configuration of the noble gas, Ne, C4− ions will be formed. 
• But again, a huge amount of energy is required. Moreover, in C4+ ions it is difficult for 6 protons to hold 10 electrons. 
• Hence, to satisfy its tetravalency, carbon shares all four of its valence electrons and forms covalent bonds.

Bonding in Hydrogen:

• The simplest molecule formed in this manner is that of hydrogen. As we know that the atomic number of hydrogen is 1. 
• Hence hydrogen has one electron in its K shell and it requires one more electron to fill the K shell. 
• So two hydrogen atoms share their electrons to form a molecule of hydrogen, H2. 
• This allows each hydrogen atom to attain the electronic configuration of the nearest noble gas, helium, which has two electrons in its K shell. 
• The shared pair of electrons is said to constitute a single covalent bond between the two hydrogen atoms.

Hydrogen Bonding: Forming Covalent Bonds in Hydrogen Molecules

• In the case of oxygen, we see the formation of a double bond between two oxygen atoms. 
• This is because an atom of oxygen has six electrons in its L shell (the atomic number of oxygen is eight) and it requires two more electrons to complete its octet.
• So each atom of oxygen shares two electrons with another atom of oxygen to give us the structure shown in. 
• The two electrons contributed by each oxygen atom give rise to two shared pairs of electrons. This is said to constitute a double bond between the two atoms.

Triple Bonding in Nitrogen: Achieving Noble Gas Configuration through Shared Electrons

• Each nitrogen atom has five electrons in the valence shell (2, 5). 
• It requires three electrons to acquire the nearest noble gas configuration (Ne).
• Therefore, both atoms share three electrons each and form a triple bond.

Allotropes of Carbon: Exploring Diamond, Graphite, and Fullerene Structures

• Meaning: The phenomenon of the existence of the same element in different physical forms with similar chemical properties is known as allotropy.
• Some elements like carbon, sulphur, phosphorus, etc., exhibit this phenomenon.
• Crystalline Allotropes of Carbon: It includes diamond, graphite and fullerene.
• Amorphous Allotropes of Carbon: It includes coal, coke, charcoal, lamp black and gas carbon.
• Diamond: Diamond has a regular tetrahedral geometry. 
• This is because each carbon is connected to four neighboring carbon atoms via single covalent bonds, resulting in a single unit of a crystal. 
• These crystal units lie in different planes and are connected to each other, resulting in a rigid three-dimensional cubic pattern of the diamond.
• It is a good conductor of heat but a poor conductor of electricity.
• Graphite: Graphite has a soft and slippery feel and it is a good conductor of electricity.
• C60: C60, also known as Buckminsterfullerene, is the very popular and stable form of the known fullerenes. 

• It is the most common naturally occurring fullerene and can be found in small quantities in soot.
• It consists of 60 carbon atoms arranged in 12 pentagons and 20 hexagons, like in a soccer ball.
• These allotropes highlight the extraordinary diversity and properties of carbon and its compounds in various physical states.

Versatile Nature of Carbonand its compounds: The Tetravalency and Catenation of Carbon

• Tetravalency and Catenation: The fact that carbon can form single, double, and triple bonds demonstrate its versatility. 
  • It can also form chains, branching chains, and rings when joined to other carbon atoms.
  • It’s a versatile element that can be found in a wide variety of chemical combinations. 
• Carbon’s versatility is best appreciated through properties like tetravalency and catenation.
  • Tetravalency: Carbon has a valency of four, so it is capable of bonding with four other atoms of carbon or atoms of some other mono-valent element.
  • Catenation: The property of a carbon element due to which its atom can join one another to form long carbon chains is called catenation.
    • S8: In its native state, sulphur shows catenation of up to 8 atoms in the form of S8 molecule. It has a puckered ring structure.

Saturated and Unsaturated Carbon and its Compounds: Exploring the Structure and Diversity

• One of the compounds formed between carbon and hydrogen is ethane with a formula of C2H6. 
• Structure: In order to arrive at the structure of simple carbon compounds, the first step is to link the carbon atoms together with a single bond C——C.
• Hydrogen: Using the hydrogen atoms to satisfy the remaining valencies of carbon is the next step.
• Chains, Branches and Rings: In the earlier section, we have seen the carbon compounds methane, ethane and propane, containing respectively 1, 2 and 3 carbon atoms.
• Such ‘chains’ of carbon atoms can contain many more carbon atoms.
• Carbon and its compounds exhibit a remarkable diversity in structures, allowing for the formation of chains, branches, and rings. These configurations contribute to the vast array of organic compounds, showcasing the versatility of carbon in creating intricate molecular arrangements.

Functional Diversity in Carbon and its Compounds: Exploring Hydroxyl, Aldehyde, Ketone, Carboxyl, and Halogen Groups

• Hydroxyl Group (-OH): All organic compounds containing -OH group are known as alcohols. For example, Methanol (CH3OH), Ethanol (CH3−CH2−OH), etc.
• Aldehyde Group (-CHO): All organic compounds containing -CHO group are known as aldehydes. For example, Methanal (HCHO), Ethanal (CH3CHO), etc.
• Ketone Group (-C=O): All organic compounds containing (-C=O) groups flanked by two alkyl groups are known as ketones. 
• Example: Propanone (CH3COCH3), Butanone (CH3COCH2CH3), etc.
• Carboxyl Group (-COOH): All organic acids contain a carboxyl group (-COOH). Hence, they are also called carboxylic acids.  For example, Ethanoic acid (CH3COOH), Propanoic acid (CH3CH2COOH), etc.

• Halogen Group (F, CI, Br, I): The alkanes in which one or more than one hydrogen atom is substituted by- X (F, CI, Br or I) are known as haloalkanes. 
• Example: Chloromethane (CH3Cl), Bromomethane (CH3Br), etc.
• Carbon and its compounds exhibit a rich diversity of functional groups, each imparting distinct properties to the organic molecules they form. From the hydroxyl group (-OH) in alcohols to the carbonyl groups in aldehydes and ketones, the carboxyl group in carboxylic acids, and the halogen group (F, Cl, Br, I) in haloalkanes, the intricate combinations showcase the versatility of carbon in creating an array of compounds with varied applications.

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