Oxygen: Different Types of Oxides

Oxides are defined as any large or important class of chemical compounds in which oxygen is combined with another element. These are the binary compounds of oxygen. Numerous elements are naturally oxidised in either air or water so that various oxides can be found as minerals in nature. Different oxides are formed as they vary in their nature and properties. Like metals with high oxidation states form covalent oxide bonds, non-metals also form covalent oxides, which are usually molecular. In short, oxidising means dehydrogenating, especially by the action of oxygen.

Example of Oxides

There are different types of oxides, examples being calcium oxide, zinc oxide, water, etc. These are known as oxides because oxygen is combined with only one element.

Apart from these, oxide has two other forms: dioxides and trioxides.

Dioxide

It is an oxide containing two oxygen atoms in the molecule; each is bonded to an atom of the second element. This is produced by burning an element in the air.

S+O2 = SO2

Trioxides

It is an oxide containing three oxygen atoms in the molecule; each is bonded to an atom directly of a second element. SO3 is considered to be the most important trioxide.

Nature of Oxides Available

There are different types of oxides that are readily available in nature. Essentially, there are three types of oxides:

Acidic Oxide

This type of oxide combines with water to give an acidic output called an acidic oxide.

They neutralise bases such as sodium hydroxide, and then dissolve in water to give out acids known as acidic anhydrides.

Example: Sulphuric trioxide dissolves in water to form sulphuric acid (H2SO4)

SO3+H2O = H2SO4

Non-metallic metals are also acidic. The acidic oxides of non-metals get dissolved in water to form acids, which turn the blue litmus solution into red.

Basic Oxide

The oxides that produce a base with water are called basic oxides. They neutralise acids like hydrochloric acid and thus dissolve in water to give bases. They are known as basic anhydrides.

Example: CaO+H2O= Ca(OH)2

Metallic oxides are basic as when they react with water, and it turns the red litmus solution to blue.

Atmospheric Oxide

This is the metallic oxide that portrays both basic and acidic properties. When it reacts with an acid, it gives salt and water showing the basic properties, and when it reacts with an alkali, it again forms salt and water showing the acidic properties.

ZnO can reacts with both acids and with bases

Reaction With acid: ZnO + 2H+ →Zn2+ +H2​O

Reaction With base: ZnO + H2O + 2OH− →[Zn(OH)4]2−

How to write an Oxide Formula?

Since an oxide is a negatively charged oxygen atom, it will gain two electrons from another atom and is represented in the form of O2.

Given below is a method of expressing an equation:

2O2(g)+2e–→O2–

How are Oxides Classified?

The classification of oxides is as follows:

• Simple Oxides
• Mixed Oxides

Simple Oxides

Simple oxides are oxides made up of one metal or semimetal and oxygen. They carry only the number of oxygen atoms allowed by the normal valency of their metal. They can be classified as acidic, basic, atmospheric, and neutral. Aluminium oxide is one example.

Mixed Oxides

Mixed oxides are oxides made by the formation of two simpler oxides. These simpler oxides may contain either the same element or different ones. Lead dioxide and lead monoxide are some examples of mixed oxides.

What are metal oxides?

In simple words, a metal oxide is a chemical compound formed by metal and oxygen. Thus, the metals react with oxygen to form basic metal oxides. They are crystalline solids that

contain an oxide anion and a metal caution. Further, they react with acids to create salts. Bases are formed after reacting with water.

Two processes can be used to prepare them:

Direct method: Combination of the metal with oxygen

Eg: 2Ca+O2= 2CaO

Indirect method: In this, thermal decomposition of salt of carbonate, nitrates, and hydroxides takes place.

E.g.: CaCO3= CaO+CO2

Conclusion

So, the different types of oxides are made by the reaction of metals with oxygen. As elements are oxidised by oxygen in either air or water, the majority of the crust of Earth is made up of solid oxides. To conclude, an oxide is an O2- ion(molecule) shown to be a dianion of oxygen. The different types of oxides with examples and classifications give a clear vision of the oxides’ reactions and nature.