Inorganic vs Organic Chemistry: What’s The Difference?

by Lucy Bell-Young

Chemistry can be classified into several different categories based on the focus of the study. Inorganic and organic chemistry are the largest branches of chemistry. So, what’s the difference between them?

Organic chemistry focuses on compounds with carbon-based molecules, whereas inorganic chemistry studies compounds that do not contain carbon atoms. 

Continue reading to understand the similarities, differences, and relationship between organic and inorganic chemistry.

Inorganic chemistry: an overview

Inorganic chemistry studies the synthesis, chemical reactions, molecular structures, and properties (both chemical and physical) of inorganic substances. It tends to deal with simpler inorganic compounds, such as carbon dioxide, and organometallic compounds, like transition metals

Teacher writing different organic and inorganic formulas on reversible mirror wall

What is the definition of inorganic chemistry?

Inorganic chemistry focuses on describing, analysing, quantifying, predicting, and synthesising inorganic simple compounds and organometallic compounds. Unlike organic substances, these compounds do not require the biological systems of living organisms to be processed. 

Generally, inorganic compounds don’t have carbon atoms or chains of carbon atoms as molecular backbones or central roles. That being said, some inorganic substances do contain carbon atoms. These include the following: 

Allotropes of carbon

  • Graphite
  • Diamond
  • Buckminsterfullerene
  • Graphene

Non-organic compounds that contain carbon

  • Carbon dioxide
  • Carbon monoxide
  • Carbides

Salts of inorganic anions

  • Carbonates
  • Cyanides
  • Cyanates
  • Thiocyanates

Many inorganic compounds are produced naturally without the aid of biological systems, although specific conditions must be met. For example, nitrates can be produced via lightning by separating diatomic atmospheric nitrogen molecules and reacting with oxygen.

Applications of inorganic chemistry

From food processing to space stations, inorganic chemistry has a range of applications across many different industries. 

In fact, virtually all of the products we use on a daily basis are made possible with the help of inorganic chemistry. These include common household items like cleaning agents and baking soda. On an industrial scale, inorganic chemistry plays a crucial role in the manufacture of products such as fertilisers and automotive parts.

Sulfuric acid is used in synthetic fertilisers

Examples of inorganic compounds

Inorganic compounds are compounds that generally do not contain carbon. As mentioned above, there are a few inorganic compounds that do contain carbon, although not as the chemical backbone. 

Inorganic compounds include many types of acids and bases, their salt products, and water. 

Here are some of the most common inorganic compounds used in both industry and everyday life:

  • Sodium chloride – also known as common table salt, sodium chloride (NaCl) is often used as a flavouring and preservative
  • Muriatic acid – an industrial strength acid with the chemical formula HCl. Muriatic acid is used to clean metals and manufacture polyvinyl chloride and polyurethane foam. It has some impurities as a commercial product
  • Sodium hypochlorite – a cleaning agent commonly diluted and used as laundry bleach. It has the chemical formula NaOCl
  • Potassium nitrate – this inorganic compound has a wide range of applications and is often used as a food preservative, fertiliser ingredient, and in fireworks. It has the chemical formula KNO3
  • Carbon dioxide – a by-product of respiration and combustion, carbon dioxide (CO2) is essential to the photosynthesis process. It’s also a primary greenhouse gas and a major contributor to global warming. Carbon dioxide has several practical applications in industries and is often used in coolants and fire extinguishers. Although it contains carbon, CO2  is still classified as an inorganic compound
  • Ammonia – about 80% of industrially-produced ammonia is used in the manufacture of fertilisers. It has the chemical formula NH3.

Organic chemistry: overview

Organic chemistry is a branch of chemistry that focuses on compounds that contain carbon. 

While it overlaps with inorganic chemistry in many ways, organic chemistry is more closely related to biochemistry (although the chemicals being studied are much simpler than biological chemicals like proteins and hormones). 

Scientist injecting a plant on a petri dish

Definition of organic chemistry

Organic chemistry is the study of compounds that have carbon atoms as the molecular and chemical foundation. This includes compounds produced by living organisms or synthetic chemicals that have chains of carbons in them, like plastic polymers. The topics covered by organic chemistry mostly focus on hydrocarbons, functional groups, and synthetic and analytical approaches

Although many organic compounds are produced by living organisms, they aren’t necessarily direct products of biological processes. For example, hydrocarbons (also known as fossil fuels) are derived from once-living organisms, but it took millions of years of being subjected to extreme pressure and heat before hydrocarbons were formed.

Uses of organic chemistry

Organic chemistry isn’t just relevant as an academic subject – it’s an important practical science that’s used in various industries, as well as the fields of pure research, environmental science, and material science. 

For example, organic chemistry plays a vital role in the petroleum industry in terms of petroleum detection, analysis, extraction, distillation, and formulation. It’s also used to synthesise and manufacture a wide range of products including polymer materials and various pharmaceutical drugs.

Young woman pharmacist or chemist using digital tablet, while standing near the shelves with medicines in modern pharmacy

How to distinguish organic from inorganic chemistry

While organic and inorganic chemistry overlap in lots of ways, they can be easily distinguished from each other by the presence of a carbon atom. Inorganic chemistry mainly deals with substances that do not have carbon atoms as the main chemical and molecular basis.

Some inorganic substances, such as diamond, do contain carbon or have carbon as a constituent. However, a carbon-containing inorganic substance is distinguished by the position and structure of the carbon in relation to the other atomic constituents. Inorganic substances are also generally much simpler compared to organic substances.

On the other hand, organic compounds have carbon atoms as the basis of their chemical, molecular, and physical properties. Organic chemistry deals with carbon-based substances that are much more complex than inorganic substances. It focuses on different types of functional groups such as alcohols, ketones, and hydrocarbon groups.

Examples of organic compounds

Organic compounds include both biologically and non-biologically produced compounds, as well as complex molecules such as proteins and carbohydrates. However, the most complex organic compounds produced by living organisms tend to fall under the field of biochemistry. 

These are the main categories of organic compounds, along with some examples:

  • Hydrocarbons – as the name suggests, these organic compounds only contain carbons and hydrogen atoms. They’re grouped into two main categories – the aromatic and aliphatic (linear, branched, and cyclic). Specific examples of hydrocarbons include methane, acetylene, and benzene.
  • Alcohols – these have hydroxyl as a functional group attached to a hydrocarbon group. The most common example of alcohol is ethanol, which is the main active ingredient of alcoholic beverages such as wine and beer.
  • Amines – amines are basic compounds that have a functional group of a nitrogen atom with a lone pair of electrons. One of the most common examples of amine is methylamine, which is a derivative of ammonia. It has a strong ammonia-like odour and is commonly used to treat water and manufacture agricultural chemicals and paints. 
  • Amides – these compounds contain a carbonyl carbon attached to an amino group as the functional group. Amino acids that are linked together through the formation of an amide are called peptides. Examples of amides are paracetamol, the fibre nylon, and the protein fibres in the skeletal muscles.

Overlaps in the chemical industry

There are overlaps between organic and inorganic chemistry, especially in the chemical industry. Many chemical processes involve both inorganic and organic chemical methods. For example, sulphuric acid is used as a reagent in the manufacture of medicines that aid in the alkylation process of DNA. 

Are metals organic or inorganic?

Metals occur in nature either as elements or as alloys. When they chemically react with other substances they lose their metallic properties such as malleability and electric conductivity. 

Even metals that contain traces of carbon (for example, steel) are not chemically bonded to carbon, nor does carbon serve as the dominant backbone element. All metals are therefore considered inorganic substances.

Are vitamins organic or inorganic?

Vitamins are organic micronutrients produced by plants and animals. They mainly serve as coenzymes and are required by the human body to facilitate metabolic processes. Vitamins are classified into two main groups – fat-soluble vitamins and water-soluble vitamins.

Foods rich in vitamin C shown around a chalk board saying 'vitamin C'

The fat-soluble vitamins include the following:

  • Vitamin A: carotenoids and retinoids
  • Vitamin D: ergocalciferol (produced by the skin with the aid of UV) and cholecalciferol
  • Vitamin E: alpha-tocopherol
  • Vitamin K: phylloquinone and menaquinones

Meanwhile, the water-soluble vitamins are:

  • Vitamin C: ascorbic acid
  • Vitamin B1: thiamine
  • Vitamin B2: riboflavin
  • Vitamin B3: niacin
  • Vitamin B5: pantothenic acid
  • Vitamin B6: pyridoxine
  • Vitamin B7: biotin
  • Vitamin B9: folate
  • Vitamin B12: cobalamin

All vitamins are organic because they contain carbon in various arrangements and chemical combinations, as well as other functional groups or elements. 

Is nitric acid organic or inorganic?

Nitric acid is one of the seven strong acids. It’s an inorganic acid with the chemical formula HNO3. Its primary use is the industrial production of ammonium nitrate, which is a major component of fertilisers. About 75-80% of the industrially produced nitric acid is used in the manufacture of fertilisers.

Summary

While the fields of inorganic and organic chemistry overlap, there are some key differences between them. Organic chemistry focuses on carbon-containing compounds produced by living organisms or synthetic chemicals that have chains of carbons in them. In contrast, inorganic chemistry generally deals with compounds that do not contain carbon atoms (although there are a few exceptions). Both inorganic and organic chemistry play crucial roles in a variety of scientific and industrial processes.

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