What is an inorganic compound?

Inorganic compounds are chemical compounds that do not contain carbon-hydrogen (C-H) bonds. They are typically derived from minerals and non-living sources. Inorganic compounds can be classified into several categories, including acids, bases, salts, oxides, and metals.

Inorganic substances do not have a carbon skeleton characteristic of organic substances.

There is a classification into simple and complex substances.
1. Simple substances consist of atoms of one element.
2. Complex substances contain two or more atoms of different elements.

Simple substances counts 4 main groups: base metals (for example, Na, Ca, Mg, K, Li and other metals from periodic table of chemical elements), nonmetals (elements like H, He, O, C et etc, which are located in the right corner of the Table), amphoteric simple substances (elements, including Al, Zn, Be, Sn, Pb, Cr, Fe et etc, show basic or acidic properties according to the conditions). We are highlighting the last one because they have unique chemical properties.

The classification of complex substances is a little bit more difficult.

  1. Oxides.

Acid oxide typically consist of nonmetal cations and oxide anions and are formed when a nonmetal reacts with oxygen. Examples include carbon dioxide (CO2), sulfur dioxide (SO2), and nitrogen dioxide (NO2).

Basic oxides are are obtained as a result of reaction of metal with oxygen. They can react with water to produce bases. Basic oxides typically consist of metal cations and oxide anions. Examples include calcium oxide (CaO), sodium oxide (Na2O), and magnesium oxide (MgO). 

Amphoteric oxides, on the other hand, are oxides that can act as both acidic and basic compounds. This means that they can react with both acids and bases. Amphoteric oxides contain elements that have the ability to donate or accept protons, allowing them to exhibit both acidic and basic properties. Some common examples of amphoteric oxides include aluminum oxide (Al2O3) and zinc oxide (ZnO). 

2. Bases

Hydroxides or bases are chemical compounds that contain the hydroxide ion (OH-) as their main component. They are formed when a metal reacts with water or when a base is dissolved in water. Bases are typically solid substances and have a basic or alkaline nature. Some common examples include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), and magnesium hydroxide (Mg(OH)2).

Bases can be corrosive and can cause burns or irritation if they come into contact with the skin or eyes. Therefore, it is important to handle them with care and follow proper safety precautions when using or working with these compounds.

3. Acids

Acids are chemical compounds that release hydrogen ions (H+) when dissolved in water. Inorganic acids are compounds that do not contain carbon atoms in their molecular structure. They have a sour taste and can react with metals to produce hydrogen gas, with bases, and other compounds. Acids have a pH value less than 7 and are known for their ability to donate protons or accept electrons.

Some examples of inorganic acids include hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), phosphoric acid (H3PO4), and hydrofluoric acid (HF). Moreover, there is a strength of an acid. Examples of strong acids are hydrochloric acid (HCl), hydroiodic acid (HI), hydrobromic acid (HBr), perchloric acid (HClO4), nitric acid (HNO3) and sulfuric acid (H2SO4). Strong acids lose protons more easily than weak ones.

4. Salts

Salts are compounds that are formed when an acid reacts with a base. In the case of inorganic acids, they can react with different bases to form various types of salts. Some common types of salts include:

– Metal salts: When an inorganic acid reacts with a metal hydroxide or metal oxide, there is a metal salt. Examples include sodium chloride (NaCl), potassium sulfate (K2SO4), and calcium phosphate (Ca3(PO4)2).

– Ammonium salts: These salts are created when an inorganic acid reacts with ammonia (NH3). For instance, ammonium chloride (NH4Cl), ammonium sulfate ((NH4)2SO4), and ammonium nitrate (NH4NO3).

– Acid salts: These salts are formed in case of a reaction an inorganic acid with a base that is not fully neutralized. They still contain some acidic properties. Examples include sodium dihydrogen phosphate (NaH2PO4), potassium hydrogen sulfate (KHSO4), and calcium hydrogen carbonate (Ca(HCO3)2).

– Double salts: They create double salts when two different salts crystallize together to form a compound with a unique chemical composition. Examples include alum (potassium aluminum sulfate, KAl(SO4)2·12H2O) and Mohr’s salt (ammonium iron(II) sulfate, (NH4)2Fe(SO4)2·6H2O).

– Hydrated salts: These salts contain water molecules within their crystal structure. The water molecules are referred to as water of hydration. Examples include hydrated copper sulfate (CuSO4·5H2O), hydrated magnesium sulfate (MgSO4·7H2O), and hydrated sodium carbonate (Na2CO3·10H2O).