A compound is a substance formulated of two or more components. For instance, water, table salt, etc.

There are two types of chemical compounds

• Covalent Compounds
• Ionic compounds

The compounds containing covalent bonds are known as covalent compounds. A covalent compound is composed of molecules. Moreover, it is also known as molecular compounds. 

A covalent compound is formulated of two or more non-metal elements, so this is one of the ways to recognise a covalent compound.

There are two basic types of covalent bonds

• Polar covalent bond: It is a covalent bond that shares the pair of electrons between two atoms of different electronegativity. For example, HCl.
• Non-polar covalent bond: It shares equal electrons between two atoms. For example, C6H6, CO2, gasoline, toluene, some noble gases, etc.

Examples of some covalent compounds

H2O – water

Carbohydrates (sugars and starch)

O3 – ozone

H2 – hydrogen

PCl3 – phosphorus trichloride

Nucleic acids (DNA and RNA)

CH4 – methane

CO2 – carbon dioxide

O2 – oxygen

CH3CH2OH – ethanol

Cl2 – chlorine

NH3 – ammonia

HCl – hydrogen chloride

Proteins

Lipids (fats)

Types of covalent bonds

There are three types of covalent bonds:

• Single covalent bond
• Double covalent bond
• Triple covalent bond

A covalent bond is formed between atoms by the sharing of electrons. When we say sharing, both the atoms need to contribute to bond formation. It indicates that each atom will provide at least one electron. Moreover, this tells us that the covalent bond will involve a minimum one pair or two electrons.

Such a type of bond where one pair of electrons are shared between atoms is called a single covalent bond. It is denoted by drawing a single line between two atoms.

Examples of single covalent compounds are:

• Hydrogen
• Methane
• Chlorine

If two pairs of electrons are shared between atoms, it is called a double covalent bond. It is represented by two lines written between the two atoms.

Examples of double covalent bonds are:

• Nitrogen
• Oxygen
• Carbon

Three pairs of electrons or simply six electrons shared between atoms are called a triple covalent bond.

Examples of triple covalent bonds are:

• Nitrogen gas
• acetylene
• the cyanide ion
• carbon monoxide

Also, carbon can form all three covalent bonds with different elements.

Simple covalent bond

For naming a simple covalent compound, there are several rules. The rules are as follows:

• First, name the first element, and after that, the second element.
• If there is more than one atom of the first element, then numerical prefixes should be used. We can determine simple covalent compound chemical formulas from its name only.
• On the other hand, if we want to determine the name of a simple covalent compound, it can be done from its chemical formula.
• We use ordinary or popular phrases/words for some simple covalent compounds instead of standardised names. 

NH3: ammonia

H2O: water

CH4: methane

Also, Methane is said to be the simplest organic compound.

Exception

It can be determined that it is a covalent compound if a molecule comprises only non-metals. However, there is one significant exception. In addition, the ammonium cation (NH4+) forms ionic bonds with nonmetals instead of covalent bonds because it is electropositive. So, it is an ionic compound.

The bonds between the hydrogen and nitrogen atoms are covalent at the exact period. So, compounds like ammonium nitrate ammonium chloride include ionic and covalent bonds.

Properties of covalent compounds

• They are gases (CO2), liquid (H2O), or soft solids (candles).
• They have low melting points. 

For instance, ice melts at 0°C.

Exception: Molecules of diamond and silica are exceptions because they have a high melting point.

• It has a low boiling point. For example, Chloroform boils at 62°C, benzene at 80.2°C.
• Non-conductors of electrical charge are one of the properties of covalent compounds. Liquid or molten do not conduct electricity.
• Covalent compounds are bad conductors of heat.
• The affinity is very less between their molecules.

Conclusion

In the article, we have discussed several things, i.e., what are covalent compounds, their introduction, examples of covalent compounds, types of covalent compounds, simple covalent compounds, exceptions, their properties, etc. We have done a brief explanation of every aspect. At last, while studying for covalent compounds, students can refer to this article to make their theory concept clear.