What are metal oxides?

We explain what metal oxides are, how they are obtained, are named and what they are used for. Also, what are non-metallic oxides.

1. What are metal oxides?

In chemistry , a type of binary molecular compounds is called basic oxides or metal oxides . Its basic formula can be expressed as follows:

X ₂ O _n

Where X is the metallic element and n is the valence of said metal. That is to say, they are formed by an oxygen atom (O) with valence -2 and an atom of any metallic element . Because of this composition they are called metal oxides.

They are also called basic oxides because they react with water forming hydroxides , also known as bases . These types of compounds are quite common in everyday life since the most abundant chemical elements in the periodic table are, precisely, the metallic ones .

Metal oxides retain some of the properties of the metal element, such as being good conductors of electricity and heat , or having high melting points . In addition, they are presented in the three states of aggregation of matter.

2. How are metal oxides obtained?

Metal oxides, as we have said before, are obtained when any metal is reacted with oxygen , for example, that present in water or air . It is what happens with the metals that we see oxidize daily. This relationship is usually expressed in the following formula :

Oxygen (O) + Metallic Element (X) = Basic or metallic oxide .

3. Nomenclature of metal oxides

When naming the basic oxides, according to the IUPAC and the traditional nomenclature, we must observe the oxidation numbers or valences of each element involved. Thus, the prefix representing the oxidation number of the element will be used in the formulation of the name. For example:

• When the element has a unique oxidation number , such as gallium (Ga), it will be named X oxide, in this case gallium oxide.
• When the element has two oxidation numbers , such as lead (Pb), it will be named depending on the valence used by the metal: the suffix –oso (less valence) or –ico (greater valence) will be used, in this case: oxide Plumbose and plumic oxide.
• When the element has three oxidation numbers , such as chromium (Cr), a similar method will be used: with the greatest valence the suffix -ico will be used, for the intermediate the suffix -oso and for the lowest valence the suffix -oso and the hypo- prefix will be preceded, as follows: chromic oxide, chromium oxide and hypochromic oxide.
• When the element has four oxidation numbers , such as manganese (Mn), a similar but more complex method will be used: with the greater valence the prefix per- and the suffix -ico will be used; with the second valence (from highest to lowest) the –ico suffix will be used; with the third valence the suffix -oso will be used; and with the lowest valence the prefix hypo- and the suffix –oso. As follows: permanganic oxide, manganic oxide, manganous oxide, hypomaginous oxide.

4. Uses of metal oxides

Metal oxides have a gigantic application in everyday life, in the manufacture of various chemical substances. Some examples of this are:

• Magnesium oxide for the preparation of medicines intended for the stomach, and in the manufacture of antidotes for poisoning.
• Zinc oxide for the manufacture of paints , dyes and dye pigments.
• Aluminum oxide for alloys of enormous hardness and other metals for industrial use.
• Lead oxide in glass manufacturing.

5. Importance of metal oxides

Metal oxides are extremely important for human beings and contemporary industries, as they serve as an accessory in many compounds of daily application .

In addition, they are the raw material in chemical laboratories to obtain bases and other compounds , since their abundance makes them much easier to obtain and handle.

6. Examples of metal oxides

Some additional examples of metal oxides are:

• Sodium Oxide (Na ₂ O)
• Potassium Oxide (K ₂ O)
• Calcium Oxide (CaO)
• Cupric Oxide (CuO)
• Ferrous Oxide (FeO)
• Lead Oxide (PbO)
• Aluminum Oxide (AlO ₃ )

7. Non-metallic oxides

Oxides nonmetallic , ie those in which the oxygen is joined to a nonmetallic element, known as anhydrides . The most common of these is the carbon dioxide (CO ₂ ) that we expel in the breath and that the plants consume to perform photosynthesis .

These compounds are very important in biochemistry . Unlike metallic ones they are not good conductors of electricity and heat . When they are reacted with water, acids are obtained.