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Covalent Network Solids

 Covalent Network Solids: Properties & Examples

“Covalent network solids: where stability meets structure.”

It is a type of crystalline solid wherein atoms are bonded together in a three-dimensional network through covalent bonds.

Covalent network solids, such as diamond, graphite, and quartz, are a fascinating class of solids held together by strong covalent bonds.

 Covalent Network Solids

These solids possess a three-dimensional network structure, making them highly stable and rigid. With their unique bonding arrangement, covalent network solids showcase the remarkable strength of chemical bonds and the intricate organization of atoms.

Characteristics of Covalent Network Solids

Covalent network solids, also known as strong covalent or amorphous solids, possess unique characteristics that set them apart from other types of materials.

Let’s take a closer look at these distinctive features:

High Melting and Boiling Points

One defining characteristic of covalent network solids is their exceptionally high melting and boiling points.

This is primarily due to the presence of strong covalent bonds between the atoms within the solid structure. These bonds are formed when atoms share electrons, creating a robust lattice-like arrangement.

Insolubility in Water and Solvents

Unlike many other substances, covalent network solids are often insoluble in water and other solvents.

The reason behind this lies in the strength of the covalent bonds holding the solid together. These bonds are incredibly powerful and require a significant amount of energy to break apart. As a result, water molecules or solvents are unable to penetrate the solid structure effectively.

Low Electrical Conductivity

Covalent network solids typically exhibit low electrical conductivity.

This is because their electrons are tightly bound within the covalently bonded structure, making it difficult for them to move freely and carry an electric charge.

Unlike metals or ionic compounds that have free-moving electrons, covalent network solids lack this ability due to their strong bonding nature.

Comparison between Covalent Network and Ionic Solids

Comparison between Covalent Network and Ionic Solids

Covalent Network Solids

Ionic Solids

Made up of atoms held together by covalent bonds Made up of ions held together by ionic bonds
Have a high melting point Have a high melting point
Do not conduct electricity in solid state Do not conduct electricity in solid state
Brittle and hard Brittle and hard
Examples include diamond, graphite, and quartz Examples include sodium chloride, magnesium oxide, and calcium fluoride

Unlike ionic solids, covalent network solids do not consist of charged ions but instead contain neutral atoms or molecules.

Covalent network solids are made up of a vast network of covalent bonds that hold the atoms or molecules together.

These bonds are formed when electrons are shared between neighboring atoms, creating a strong and stable structure. In contrast, ionic solids are composed of positively and negatively charged ions held together by electrostatic forces..

While ionic compounds dissolve easily in water, most covalent network solids do not readily dissolve in any solvent.

Ionic compounds possess an ability called “solubility” which allows them to dissolve easily in polar solvents like water due to their charged nature.

The positive and negative ions separate from each other when dissolved in water, forming an aqueous solution.

Conversely, most covalent network solids do not readily dissolve in any solvent because their strong covalent bonds make it difficult for them to break apart and interact with the solvent molecules.

Unique Properties of Diamond

Diamond, a covalent network solid, possesses some remarkable properties that set it apart from other materials. Let’s explore these unique characteristics!

A beautiful sparkling diamond on a light reflective surface. 3d image. Isolated white background.

Hardness and Structure

Diamond is renowned for being the hardest known natural material.

This exceptional hardness can be attributed to its strong carbon-carbon bonds arranged in a tetrahedral lattice structure.

The carbon atoms form a three-dimensional network where each carbon atom is bonded to four neighboring carbon atoms. This tightly packed arrangement results in an incredibly rigid structure, making diamond resistant to scratching and deformation.

Thermal Conductivity

Another fascinating property of diamond is its exceptional thermal conductivity.

It has the ability to efficiently transfer heat due to the highly ordered arrangement of its carbon atoms. This makes diamond an ideal material for applications requiring excellent heat dissipation, such as heat sinks in electronics.

By effectively dissipating heat, diamond helps prevent overheating and ensures optimal performance of electronic devices.

Optical Dispersion and Brilliance

Diamond also exhibits high optical dispersion, which gives rise to its brilliant sparkle and makes it highly sought after as gemstones.

When light enters a diamond, it undergoes multiple reflections within the crystal lattice before emerging back out. This dispersion causes different colors of light to separate and scatter, creating a dazzling display of spectral colors.

Structure and Properties of Graphite

Graphite is a unique form of carbon with its own set of interesting properties. Let’s take a closer look at the structure and properties of this fascinating substance.


Layers of Carbon Atoms

Graphite consists of layers of carbon atoms arranged in a hexagonal lattice structure.

These layers are held together by weak van der Waals forces. Unlike diamond, which has strong covalent bonds between each carbon atom, graphite’s structure allows for easy movement between layers.

Slippery Feel and Lubrication

Due to the weak interlayer forces, graphite has a slippery feel to it. This property makes it an excellent lubricant in various applications.

When used as a lubricant, the layers slide over each other easily, reducing friction and wear.

Conductivity and Insulation

While graphite is an excellent conductor of electricity along the layers, it acts as an insulator perpendicular to them.

The delocalized electrons within the hexagonal lattice structure allow for efficient electron flow along the layers, making graphite conductive. However, when current tries to pass through the layers perpendicularly, it encounters resistance due to the lack of available pathways for electron movement.


The unique properties of graphite make it useful in several industries:

  • Lubrication: Graphite’s slippery nature makes it ideal for lubricating machinery parts.
  • Batteries: Graphite is commonly used as an electrode material in batteries due to its electrical conductivity.
  • Pencils: The “lead” in pencils is actually made from graphite mixed with clay.
  • Heat Dissipation: Graphite’s high thermal conductivity makes it effective at dissipating heat in electronic devices.

Quartz: A Covalent Network Solid with Remarkable Features

Quartz, a crystalline form of silicon dioxide (SiO2), is an example of a covalent network solid. This means that its structure consists of silicon and oxygen atoms arranged in a continuous three-dimensional lattice.

One remarkable feature of quartz is its piezoelectric properties.


When subjected to mechanical stress, such as pressure or vibration, quartz can generate an electric charge.

This property makes it highly valuable in various applications, particularly in electronic devices like watches and oscillators that require precise frequency control.

Quartz’s unique lattice structure contributes to its exceptional characteristics. It forms a continuous network of interconnected silicon-oxygen bonds throughout the crystal, resulting in a strong and rigid framework. These covalent bonds are incredibly stable and difficult to break, giving quartz its high melting point.

The covalent nature of the bonding in quartz also affects its electrical conductivity.

Unlike metals that have free-moving electrons allowing for easy flow of electricity, quartz does not conduct electricity efficiently due to the absence of free electrons. However, it can exhibit semiconducting behavior under certain conditions.

Another interesting aspect of quartz is its presence in different forms other than crystalline structures. Amorphous varieties such as glass also consist of silicon dioxide molecules but lack long-range order found in crystals. Instead, their arrangement is more random and disordered.

Other Examples of Covalent Network Solids

Silicon carbide (SiC) is a covalent network solid that finds extensive use in high-performance ceramics and abrasive materials.

It has a crystalline structure consisting of silicon and carbon atoms bonded together with strong double bonds. This gives silicon carbide its exceptional hardness and thermal conductivity, making it ideal for applications in cutting tools, grinding wheels, and even bulletproof vests.

Boron nitride (BN), on the other hand, shares a similar structure to graphite but possesses remarkable thermal stability and electrical insulation properties. It is composed of boron and nitrogen atoms arranged in a hexagonal lattice, forming layers held together by weak van der Waals forces. Boron nitride exhibits excellent lubricating properties at high temperatures, making it useful as a solid lubricant in industrial applications.


We discussed their characteristics, compared them to ionic solids, and delved into the unique properties of diamond, graphite, and quartz.

By understanding these materials on a deeper level, you can gain insight into their applications and appreciate their remarkable features.

Now that you have a better understanding of covalent network solids, you might be wondering how they impact our daily lives.

These materials play a crucial role in various industries such as electronics, construction, and jewelry manufacturing. From the durability of diamond engagement rings to the conductivity of graphite in electronic devices, covalent network solids are essential for technological advancements.

If you’re interested in learning more about different types of covalent network solids or exploring their practical applications further, don’t hesitate to continue your research or reach out to experts in the field.

By staying curious and expanding your knowledge on this subject, you can discover even more exciting aspects and potential uses for these extraordinary materials.


What are some other examples of covalent network solids?

Some other examples of covalent network solids include silicon carbide (SiC), boron nitride (BN), tungsten carbide (WC), and aluminum oxide (Al2O3). These materials possess unique properties that make them valuable in various industries.

Can covalent network solids conduct electricity?

Most covalent network solids do not conduct electricity because they lack free electrons or mobile charge carriers. However, there are exceptions like graphite which exhibits electrical conductivity due to its unique layered structure.

Are all diamonds clear?

No, not all diamonds are clear. While most diamonds appear colorless or white due to their high transparency, diamonds can also exhibit various colors such as yellow, brown, blue, green, pink, and even black.

How are covalent network solids different from ionic solids?

Covalent network solids are composed of atoms held together by strong covalent bonds, while ionic solids consist of positively and negatively charged ions held together by electrostatic forces. This fundamental difference in bonding leads to distinct properties and behaviors between the two types of solids.

Can covalent network solids be dissolved in water?

In general, covalent network solids are not soluble in water because their strong covalent bonds make them resistant to dissolution. However, some exceptions exist, such as certain forms of silicon dioxide (quartz) that can dissolve in water under specific conditions.


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