Organic compounds: what they are, characteristics, classification and examples

What are organic compounds?

Organic compounds (or organic molecules) are those that come from living beings, that is, they are compounds of biological origin, which are characterized by having carbon as the main element.

This means that all organic compounds contain carbon, although not all compounds that contain carbon are organic.

Organic compounds are present in all living things, their remains, and their products. Therefore, they represent the majority of known compounds. Although they are synthesized by organisms (such as petroleum), some can be obtained through the artificial synthesis in laboratories (such as vitamin C).

Generally, the elements that participate in organic compounds are carbon and hydrogen, followed by nitrogen, oxygen, phosphorus, and sulfur. These are non-metal elements, and one of their characteristics is to join through covalent bonds, that is, bonds in which they share electrons.

Some examples of organic compounds are:

• proteins, such as enzymes, muscle fibers, and antibodies;
• lipids, present in oils and butter; also cholesterol and triglycerides in the blood; waxes and steroids;
• carbohydrates, such as glucose, sucrose, and fructose;
• hydrocarbons, such as benzene or oil and its derivatives (gasoline, kerosene, etc.);
• nucleic acids, such as DNA or RNA.

Organic compounds are the object of study of organic chemistry.

Characteristics of organic compounds

Within the diversity of organic compounds that exist, they all share a series of characteristics. Namely:

• They always have carbon as their main element, almost always bonded to hydrogen. Less frequently, they present nitrogen, oxygen, phosphorus, and sulfur.
• They form stable covalent bonds, which give rise to linear, branched, or cyclic chains.
• They can be liquid, solid, or gaseous.
• They are not good conductors of electricity.

Properties of organic compounds

We call properties of organic compounds those attributes of their nature that characterize their behavior. Among the most important we can mention the following:

• They are combustible: most organic compounds have the property of burning in the presence of oxygen.
• They have solubility: some organic compounds are soluble in organic solvents, such as plastic in gasoline, while others are soluble in water, such as alcohol and sugar.
• They present isomerism: it is the property of forming different compounds with the same number of atoms. For example, fructose and glucose are different compounds that have the same number of carbon, hydrogen, and oxygen atoms.
• They can present aromaticity: certain organic compounds present aroma because they have a ring structure with intercalated single and double bonds. For example, products with benzene such as gasoline, paints, and solvents.
• Boiling and Melting Points: Organic compounds typically have low boiling and melting points.

Classification of organic compounds

There are many ways to classify organic compounds, each of which response to different needs. The classifications can respond to their origin, their functional groups, their structure, and their polarity, among other criteria.

Types of organic compounds according to their origin

According to the origin of the organic compounds, these can be natural or artificial.

• Natural organic compounds: are those from living beings or their remains. For example, chlorophyll and amino acids.
• Artificial organic compounds: are those that can be artificially synthesized in chemical laboratories. For example, plastics and synthetic fibers.

Types of organic compounds according to their structure

When we talk about structure, we mean the way carbon atoms bond with each other. They can be aliphatic, aromatic, or heterocyclic.

• Aliphatic compounds: are those that form chain structures, whether linear or branched. For example, hydrocarbons such as propane.
• Aromatic compounds: are those that form ring structures, from which the property of aromaticity derives. For example, naphthalene (C ₁₀ H ₈ ) and benzene (C ₆ H ₆ ).
• Heterocyclic compounds: their structure is made up of carbon rings linked to other elements, such as nitrogen. For example, saccharin (C ₇ H ₅ NO ₃ S).

Types of organic compounds according to their functional groups

Functional groups are present in some organic compounds, which are groups of atoms arranged in a specific way that determine how the compounds react. Thus, organic compounds can be:

• Alcohols: It is formed with carbon attached to a hydroxyl group OH.
• Ethers: are formed when a carbon chain has an intercalated oxygen atom.
• Esters: result from the combination of an alcohol with an organic acid.
• Organic acids: formed by carbon attached to a carboxyl group.
• Aldehydes: result from the union of carbon with a carbonyl group, that is, a group formed by carbon and oxygen.
• Amines: they are formed by the union of carbon to an amine group -NH3.

Types of organic compounds according to their polarity

Polarity arises when the distribution of electrons in molecules is unequal. This is a constant condition for inorganic compounds, but not for organic ones. Therefore, organic compounds can also be classified as polar and nonpolar.

• Polar organic compounds: are those organic compounds whose carbon and hydrogen bonds present other chemical elements such as nitrogen, oxygen, phosphorus, and sulfur, resulting in an unequal distribution of electrons.
• Nonpolar organic compounds: are those that only have carbon and hydrogen and, therefore, the distribution of their electrons is uniform.

examples of organic compounds

Below, we present a list of some organic compounds present in everyday life and their most common or well-known uses.

1. Acetone (CH ₃(CO)CH ₃ ), varnish remover.
2. Acetic acid (H ₃CCOOH), is a component of vinegar.
3. Formic acid (HCOOH) is a defensive substance of ants.
4. Isopropyl alcohol (C ₃H ₈ O), epidermal disinfectant.
5. Benzene (C ₆H ₆ ), a gasoline additive, some detergents, dyes, and others.
6. Butane (C ₄H ₁₀ ), fuel gas.
7. Dichlorodiphenyltrichloroethane or DDT, insecticide.
8. Ethanol (C ₂H ₃ OH), is a component of alcoholic beverages.
9. Formaldehyde (CH ₂O), is a preservative of living tissues.
10. Glycerin or Glycerol (C ₃H ₈O ₃ ), antifreeze agent.
11. Glucose (C ₆H ₁₂O ₆ ), is a simple sugar that provides energy to living beings.
12. Hexane (C ₆H ₁₄), solvent.
13. Methane (CH ₄), is a greenhouse gas.
14. Naphthalene or naphthalene (C ₁₀H ₈), moth repellent.
15. Nylon, material for textile manufacturing.
16. Polystyrene is, the material to make anime.
17. Propane (C ₃H ₈), fuel gas.
18. Sucrose (C ₁₂H ₂₂O ₁₁ ), sweetener.
19. Trichloromethane or chloroform (CHCl ₃), fat solvent.
20. Trinitrotoluene or TNT ( _{C7H5N3O6 ) , explosive}.

Difference Between Organic Compounds and Inorganic Compounds

The first difference between organic and inorganic compounds lies in their origin. While organic compounds come from living things and their remains, inorganic compounds come mostly from the earth's crust.

Inorganic compounds are usually made up of metallic and non-metallic elements, while organic compounds always have carbon as the main element.

Most organic compounds are formed by covalent bonds, while inorganic compounds are generally formed by ionic bonds.

Organic and inorganic compounds also differ in their properties. Inorganic compounds are good conductors of electricity when dissolved in water; instead, organics are never good conductors of electricity.

Unlike organic compounds, inorganic compounds do not exhibit concatenation, isomerism, or aromaticity. Also, they are rarely combustible. Inorganic compounds only reach melting points at very high temperatures.

	organic compounds	inorganic compounds
Origin	Biological	Non-biological
Elements	Carbon (always), hydrogen (almost always), oxygen, nitrogen, phosphorus, and sulfur	metal elements and non-metal elements
Links	covalent	mostly ionic
isomerism	Yes	No
conduction of electricity	No	Yes
Combustibility	Yes	Rarely
aromaticity	Yes	No
Melting and boiling points	Low	tall

 

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