Classification of Organic Compounds

The compounds which contain carbon in their molecule are known as organic compounds. The organic compounds we get from earths crust in very small percentage, but the importance of organic compounds in all living things is much more. The number of compounds that contain carbon are much more than the compounds which do not contain carbon. So, to understand organic compounds they should be properly classified. Organic compounds are classified as acyclic (open chain) and cyclic (closed chain). In this article we will discuss about what are the organic compounds and classification of organic compounds.

What is an Organic Compound

Organic compound is a large class of chemical compound in which one or more atoms of carbon are covalently linked to atoms of other elements. Most commonly it linked to hydrogen, oxygen or nitrogen.

A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. This electron pairs are also known as shared pairs or bonding pairs.

There are two large reservoirs of organic material from which simple organic compounds can be obtained from petroleum and coal (petrochemicals). Petrochemicals are formed from the high pressure and temperature degradation of organic matter.

The carbon atom posses the catenation property. Catenation is the self-linking property of atoms of an element to create chains and rings. Because of this property, carbon forms number of organic compounds.

Classification of Organic Compounds

Organic compounds are classified mainly as acyclic (open chain) and cyclic (closed chain).

  1. Acyclic (open chain)
    • Straight Chain
    • Branched Chain
  1. Cyclic (closed chain)

a. Homocyclic

    • Alicyclic
    • Aromatic

b. Heterocyclic

    • Saturated
    • Unsaturated –   i. Aromatic                   ii. Non-aromatic
classification of organic compounds
classification of organic compounds

 

Acyclic or Open Chain Compounds

In acyclic organic compounds carbon atoms are linked to each other in linear structure. Acyclic organic compound also called as aliphatic compounds. They are classified as straight chain and branched chain.

Straight chain organic compounds

Straight chain organic compound consist of carbon atoms connected in a linear structure (straight line).

Branched chain organic compounds

Branched chain organic compounds contain side chain attached to a continuous linear carbon chain.

Examples: methane, ethane, butane, isobutane, isopentane.

Cyclic or Closed Chain Compounds

Organic compounds containing at least one ring or closed chain of atoms is known as cyclic or closed chain compounds.  They are further classified as homocyclic and heterocyclic.

Homocyclic compounds

The organic compound having only one carbonyl ring in their structure is known as homocyclic compounds.

Homocyclic compounds are further classified as alicyclic and aromatic compounds.

Alicyclic compounds

These compounds contain ring of three or more carbon atoms.

Aromatic compounds

Aromatic compounds consist of at least one benzene ring. It contains six-member homocyclic ring having alternate single and double bonds. Generally, these compounds have some fragrant odour.

Examples: cyclopropane, cyclobutene, cyclopentane.

Heterocyclic compounds

Heterocyclic compounds are organic compounds with at least one ring structure that contains at least one carbon atom and one another element like Nitrogen, Oxygen, Sulphur.

Heterocyclic compounds are further classified as saturated and unsaturated compounds.

Saturated Heterocyclic compounds

Heterocyclic compounds have only one carbon bond is known as Saturated heterocyclic compounds. Saturated compounds are stable compare to unsaturated compounds.

Unsaturated heterocyclic compounds

Unsaturated compounds are composed of double and triple bonded carbon atoms.

Conclusion

A catenation property of carbon increases the number of organic compounds. Hence it is necessary to classify them in a systematic way. The above classification of organic compounds helps to understand them better.

Frequently Asked Questions

1. What is the classification of organic compound?

The organic compounds are mainly classified into; acyclic compounds and cyclic compounds.

 2. What is called organic compound?

Organic compound is a large class of chemical compound in which one or more atoms of carbon are covalently linked to atoms of other elements. Most commonly it linked to hydrogen, oxygen or nitrogen.

3. What is the difference between saturated and unsaturated heterocyclic compound?

Saturated heterocyclic compounds contain single carbon bond, whereas unsaturated heterocyclic compounds contain double or triple carbon bonds.

4. How do you name organic compounds?

According to the terms provided by IUPAC to name organic compounds, a root word, a prefix and a suffix is required.

References

  1. Organic chemistry by Robert Thornton Morrison, Robert Neilson Boyd and Saibal Kanti Bhattacharjee, seventh edition.

 

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