Inorganic Compounds

What are inorganic compounds

Inorganic compounds (or inorganic molecules) are those that are formed by the combination of metal and non-metal elements from the periodic table. They generally do not contain carbon, and when they do, it is not a major element.

They receive this name because they have no biological origin. That is, they are inert matter that normally comes from the earth’s crust. They can also be generated from natural phenomena.

Inorganic compounds can be formed from metal and nonmetal elements by ionic bonds. These types of bonds occur by the transfer of electrons from metals to non-metals. Eventually, they can be formed by covalent bonds, which are only established between non-metal elements. These, instead of transferring electrons, share them.

Although it can be said that the sum of metal and non-metal elements represents the majority of the periodic table, inorganic compounds are outnumbered by organic compounds.

Some examples of inorganic compounds in everyday life are water (HtwoEITHER); salt (sodium chloride, NaCl); lime (oxocalcium or calcium oxide, CaO); ammonia (NH3); carbon dioxide (COtwo) and sodium bicarbonate (NaHCO3).

Organic compounds are the subject matter of inorganic chemistry.

Characteristics of inorganic compounds

Inorganic compounds are very varied among themselves. Within their variety, they share certain characteristics that differentiate them from organic compounds.

  • They result from the combination of metal and non-metal elements from the periodic table.
  • They are formed by ionic bonds almost always.
  • They do not present concatenation, that is, their links do not form chains.
  • Some inorganic compounds can be formed by covalent bonds, such as ammonia, water, and carbon dioxide.
  • They do not present isomerism, that is, each combination of atoms gives rise to a single compound.
  • As a general rule, they are not combustible.
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Properties of inorganic compounds

The properties of inorganic compounds refer to their behavior against certain factors. The best known properties are:

  • High melting and boiling points: Due to the characteristics of their bonds, organic compounds have much higher melting and boiling points than organic compounds.
  • They can crystallize: Due to the lack of mobility of their ions, certain inorganic compounds have the property of crystallization. For example, the salts.
  • Water solubility: most inorganic compounds are usually soluble in water, although there are some exceptions.
  • Good conduction of heat and electricity: Because they ionize, they are good conductors of electricity when dissolved in water. They are also good conductors of heat.

See also: Ionic bond

Classification of inorganic compounds

The most common way to classify the types of organic compounds is according to their functional groups.


It brings together the compounds formed by the union of oxygen with another element. They are subdivided into basic and acidic oxides.

  • Basic oxides: They combine oxygen with a metal through an ionic bond. For example, magnesium oxide (MgO), which is used in the manufacture of stomach acid antacids.
  • Acid oxides: They combine oxygen with a nonmetal through covalent bonds. For example, carbon monoxide (CO).


They are those that are formed by combinations of water with basic oxides. Therefore, in their structure they show the presence of OH. For example, sodium hydroxide (NaOH), used in the manufacture of textiles, crayons, paints, and paper.


They arise from the combination of hydrogen with elements or groups of high electronegativity. They are divided into:

  • Hydracids: combine hydrogen with a nonmetal. Its formula never presents oxygen. For example, hydrochloric acid (HCl).
  • Oxacids: they combine water with acid oxide, so their formula always has oxygen and hydrogen. For example, sulfuric acid (H₂SO₄).
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They are those that result from combining an acid with a base.

  • Oxysal: they combine oxacid acid and a hydroxide. Therefore, its formula always contains oxygen, a metal and a non-metal. For example, sodium nitrate (NaNO3).
  • Haloid salts: its structure is made up of a non-metal with a metal, and in its formation process water is produced. For example, common salt, whose chemical name is sodium chloride (NaCl).


It usually refers to compounds formed by hydrogen atoms with any metal or non-metal element of the periodic table. For example, sodium hydride (NaH).

Examples of inorganic compounds

Next, we present a list with examples of inorganic compounds present in everyday life, pointing out their origin or their best-known uses.

  1. Sulfuric acid (HtwoSW4), vehicle battery acid.
  2. Hydrochloric acid (HCl), produced by the stomach for digestion.
  3. Water (HtwoO), used in the hydration of living beings, hygiene, the agricultural industry and more.
  4. Prussian Blue Faith4(Fe(CN)6)3used as a colorant.
  5. Sodium bicarbonate (NaHCO3), has uses in cooking, cleaning, and the pharmaceutical industry.
  6. Calcium Carbonate (CaCO3), treats heartburn.
  7. Barium chloride (BaCltwo), component of fireworks.
  8. Sodium chloride (NaCl), common salt.
  9. Sulfur dioxide (SOtwo), toxic gas released from volcanic eruptions.
  10. Carbon dioxide (COtwo), gas released with respiration.
  11. Calcium Phosphate Ca3(PO4)twocomponent of bones.
  12. Sodium hydroxide (NaOH) or caustic soda, component of soaps.
  13. Hydrogen peroxide (HtwoEITHERtwo) hydrogen peroxide, used as a microbial and oxidizing agent.
  14. Sodium monofluorophosphate (NatwoPO3F), component of toothpastes.
  15. Carbon monoxide (CO), poisonous gas produced by the combustion of organic compounds.
  16. Magnesium Sulfate (MgSO4), known as fig salt, used as an anti-inflammatory, laxative and bronchodilator.
  17. Iron sulfide (FeStwo), composed of lithium batteries.
  18. Zinc oxide (ZnO), component of various cosmetics.
  19. Nitrous oxide (NtwoO) or laughing gas. It has an anesthetic effect.
  20. Potassium iodide (KI), among other uses, is a protector of the thyroid gland against radiation.
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It may interest you:

  • chemical nomenclature
  • Inorganic chemistry

Organic compounds and inorganic compounds

The main difference between organic and inorganic compounds is in their origin. While organic compounds have a biological origin, inorganic ones almost always come from the earth’s crust, such as water. However, some organic compounds can now be obtained artificially in laboratories, such as synthetic fibers or plastics.

Precisely because of their biological origin, organic molecules are much more numerous than inorganic ones.

They also differ in the number of elements involved. In organic compounds, only carbon participates, whose presence is constant, hydrogen, sulfur, oxygen, nitrogen and phosphorus. Instead, inorganic compounds can combine all of the metal and nonmetal elements on the periodic table.

Organic compounds are usually formed by covalent bonds, while organic compounds are almost always formed by ionic bonds.

Among the properties of organic compounds are combustibility, aromaticity, low melting and boiling points, solubility in organic solvents and water, and finally, isomerism (that is, the same combination of atoms can create different molecules).

Among the properties of inorganic compounds we can recognize good conduction of heat and electricity, solubility in water and high melting and boiling points.