inorganic compound

Chemistry

2022

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

Inorganic compounds are less abundant than organic ones.

What is an inorganic compound?

Unlike organic compounds, typical of the chemistry of life, inorganic compounds are those whose composition is not based primarily on carbon and hydrogen, but involves various types of elements, almost everyone known to the Periodic table.

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

Despite the variety of elements available, inorganic compounds are far less abundant and diverse than organic ones. In addition, they have a way of nomenclature different and are usually involved in different processes.

Inorganic compounds can be classified into: oxides, peroxides, hydrides, salts, hydroxides and oxacids.

What properties do they have?

Inorganic compounds have high melting and boiling points.

Inorganic substances can differ greatly from each other, so their properties are not always common or universal. In general, however, some properties can be mentioned:

  • Good drivers of heat and of electricity.
  • The ionic bond (electrovalent).
  • They have points of fusion Y boiling.
  • Some solid, they usually present hardness and fragility.
  • They are usually organized in the form of crystals when they are solid salts, due to the lack of mobility between their ions.

Types of inorganic compounds

Hydroxides result from the union of a metal with a hydroxyl group.

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

  • Binary compounds. They are those that are composed of only two chemical elements. Such as:
    • Oxides They are compounds formed by the union of oxygen (O2) with some metallic element (basic oxides) or non metallic (acid oxides) from the Periodic Table. For example: chlorine oxide (VII) or dichloro heptaoxide (Cl2O7), iron (II) oxide or ferrous oxide (FeO).
    • Peroxides Peroxides are formed by joining the peroxide group (O22-) with a metallic element. In these compounds, oxygen has oxidation number -1. For example: gold (III) peroxide (Au2 (O2) 3), lithium peroxide (Li2O2).
    • Hydrides They can be metallic and non-metallic. Metal hydrides are formed by the union of a hydride anion (H–) with a negative electrical charge, with any metal cation (positive charge). Non-metallic hydrides are formed by the union of a non-metal (which, in this case, always reacts with its lowest oxidation state) and hydrogen. Hydrides are generally gaseous and are named by prepending the name of the nonmetal followed by the phrase -of hydrogen. For example: hydride Lithium (LiH), beryllium hydride (BeH2), hydrogen fluoride (HF (g)), hydrogen chloride (HCl (g)).
    • Hydracids or binary acids. They are binary acids composed of hydrogen and a nonmetal other than oxygen. For example: hydrochloric acid (HCl (aq)), hydrofluoric acid (HF (aq)) or hydrogen selenium (H2Se (aq)).
    • Binary salts. They are compounds formed by sets of electrically charged atoms, either cations (+) or anions (-). These salts are composed of only two types of atoms. For example: calcium chloride (CaCl2), iron (III) bromide or ferric bromide (FeBr3).
  • Ternary compounds. They are compounds in which three chemical elements are involved. Such as:
    • Hydroxides They are compounds resulting from the union of a metallic element with a hydroxyl group (OH–). They are commonly called "bases" or "alkalis". For example: sodium hydroxide (NaOH), germanium (IV) hydroxide (Ge (OH) 4).
    • Oxacids. They are acidic compounds that arise from the reaction between an anhydride (a non-metallic oxide) and Water. Its formula always depends on a HaAbOc pattern, where A is a transition metal or a nonmetal, and a, b, and c are the subscripts that indicate the amount of each atom. For example: sulfuric acid (H2SO4), carbonic acid (H2CO3)
    • Ternary salts. They are compounds formed by sets of electrically charged atoms, either cations (+) or anions (-). These salts are made up of just three types of atoms. For example: lithium nitrate (LiNO3) and copper (II) sulfate (CuSO4).

Examples of inorganic compounds

Ammonia is an inorganic molecule made up of hydrogen and nitrogen.

Some commonly used inorganic compounds are:

  • Water (H2O). Despite being so abundant in the world and being indispensable for the life, water is an inorganic substance. This substance is liquid at temperature normal (25 ºC) and solid when it is cooled below 0ºC. On the other hand, when it is subjected to temperatures above 100 ºC it becomes steam.
  • Sodium chloride (NaCl). It is the common salt that we use to eat. It is made up of a sodium atom and a chlorine atom, and is found abundantly in the Earth crust, especially dissolved in the waters of the sea.
  • Ammonia (NH3). Is a molecule inorganic compound of hydrogen and nitrogen. This substance is excreted together with others (such as urea) as a waste from the metabolism of various living creatures. It usually comes in a gaseous form and has a characteristic unpleasant odor.
  • Carbon dioxide (CO2). It is a gas made up of carbon and oxygen. It is extremely abundant in our atmosphere since various metabolic processes expel it as a by-product, for example, the animal respiration, the fermentation, etc. It is, at the same time, the elementary input to carry out the photosynthesis of the plants.
  • Calcium oxide (CaO). Also called "quicklime", it is widely used in construction. It is obtained by calcining limestone or dolomite rocks, rich in mineral calcium sources.
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