What is an inorganic compound?

We explain what an inorganic compound is and its properties. In addition, the types of inorganic compounds that exist and examples.

1. What is an inorganic compound?

Unlike the organic ones, typical of the chemistry of life, inorganic compounds are those whose composition does not revolve around carbon and hydrogen , but involves various types of elements, almost all known from the periodic table.

These compounds are formed through reactions and physical phenomena present in nature, such as solar energy , the action of electricity or heat, etc., which allow the creation of various substances. The atoms and molecules of these usually join through ionic or covalent bonds .

Despite the variety of elements available, inorganic compounds  are much less abundant and diverse on our planet than organic ones. Similarly, they have a different form of nomenclature and are usually involved in different processes.

The inorganic compounds can be: oxides, hydrides, salts, hydroxides and oxyacids.

2. What properties do they have?

Inorganic substances can differ greatly from each other, so their properties are not always common nor are they universal . In general, however, it is about:

• Good conductors of heat and electricity.
• The ionic (electrovalent) bond predominates in them.
• They have high melting and boiling points.
• When they are solid, they usually have hardness and fragility.
• They are usually organized in crystals, when solid, due to the lack of mobility between their ions.

3. Types of inorganic compounds

Inorganic compounds have a variety of structures , but can be classified according to the number of elements involved in each compound, as follows:

Binary compounds . Those that consist only of two chemical elements. Such as:

• Oxides . Product of the union of oxygen (O2) with some metallic element (basic oxides) or non-metallic (acid oxides) of the periodic table. For example: chlorine oxide (VII): Cl2O7 – ferrous oxide: FeO.
• Peroxides . Peroxides are joints of the peroxide group (O2-2) with a metallic element. For example: gold peroxide (III): Au2 (O2) 3 – lithium peroxide: Li2O2.
• Hydrides . The hydrides are composed by joining a hydride anion (H-) of negative electrical charge, with any metal cation (positive charge). For example: Lithium hydride: LiH – Beryllium hydride: BeH2.
• Binary salts . These are ions, that is, sets of electrically charged atoms, either cations (+) or anions (-). These types of ions are also salts. For example: calcium chloride: CaCl2 – iron bromide: FeBr3.

Ternary compounds . Those in which three chemical elements are involved. Such as:

• Hydroxides . Resulting from the union of a metallic element with a hydroxyl group (OH-). They are commonly called “bases” or “alcalis”. For example: sodium hydroxide: NaOH – germanium (IV) hydroxide: Ge (OH) 4.
• Oxacids . Acids that arise from the reaction between an anhydride (a nonmetal oxide) and water. Its formula always depends on a HaAbOc pattern, where A is a transition metal or a nonmetal. For example: sulfuric acid: H2SO4 – carbonic acid: H2CO3.

4. Examples of inorganic compounds

Some inorganic compounds in common use are:

• Water (H 2 O) . Despite being so abundant in the world and being indispensable for life, water is an inorganic substance, liquid at normal and solid temperature when cooled below 0 ° C, capable of becoming gas (steam) when taken to the 100 ° C
• Sodium Chloride ( NaCl ) . The common salt that we use to eat, is composed of one atom of sodium and another of chlorine, and is found abundantly in the earth’s crust, especially dissolved in the waters of the sea.
• Ammonia  (NH 3 ) . An inorganic molecule composed of hydrogen and nitrogen, which is excreted along with others (such as urea) by the metabolic systems of various living things. It usually comes in a gaseous form, and has a characteristic unpleasant smell.
• Carbon dioxide (CO 2 ) . A gas composed of carbon and oxygen that is extremely abundant in our atmosphere , since various metabolic processes throw it as a byproduct: animal respiration, fermentation, etc. It is, at the same time, the elementary input to perform photosynthesis of plants.
• Calcium oxide ( CaO ) . Also called “quicklime”, it is widely used in construction and is obtained by calcining limestone rocks or dolomites, rich in sources of mineral calcium.