Name two compounds that exist as network solids at room temperature and pressure.

Chemical compounds are substances composed of two or more different types of atoms that are chemically bonded together. In the realm of network solids, the atoms are joined via covalent bonds to create vast crystalline structures. Such compounds are distinguished by their incredible stability and distinctive physical properties like high melting points and hardness.

Network solids are a unique kind of chemical compound in which an extensive network of covalent bonds creates a continuous, three-dimensional matrix. This structure grants them rigidity and strength, making them suitable for various applications ranging from abrasives like silicon carbide to gemstones such as diamond.

Covalent bonds form when two atoms share electrons, resulting in a stronger and more stable arrangement than if the atoms remained separate. This type of bond is fundamental to the formation of network solids, as it connects atoms in a durable, long-lasting matrix.

The nature of these bonds dictates the properties of the resulting material. For instance, the directional properties of covalent bonds in diamond create a three-dimensional lattice that contributes to its famed hardness. Understanding the role of covalent bonds in network solids provides insight into why these materials are so resistant to heat and have such high melting points.

Diamond is a form of carbon where each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral structure. This configuration leads to an incredibly strong and rigid lattice that makes diamond the hardest known natural material.

Unique Properties of Diamond

• Hardest known natural material
• High refractive index resulting in its brilliant sparkle
• Remarkable thermal conductivity

Additionally, due to its aesthetic appeal and durability, diamond is highly prized in jewelry and has various industrial applications, where its hardness is exploited for cutting and grinding.

Quartz, also known as silicon dioxide or SiO2, is another example of a network solid with each silicon atom covalently bonded to four oxygen atoms. The atoms form a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra.

This arrangement results in a diverse family of quartz that can be found in many different forms, from clear and colorless to colored varieties such as amethyst and citrine. It is widely used in electronics, timepieces, and as gemstones due to its piezoelectric properties, which allow it to convert mechanical pressure into electrical energy, and vice versa.

Silicon carbide, or SiC, is a compound with a network of silicon and carbon atoms. This material exemplifies the extraordinary hardness and thermal conductivity that network solids can exhibit.

Applications of Silicon Carbide

• Used as an abrasive due to its hardness, second only to diamond
• High thermal conductivity makes it suitable for high-temperature applications
• Valued in electronic devices that operate at high voltages and high temperatures

Its excellent thermal and electrical properties make it a material of choice in many demanding industrial settings, including in the manufacturing of ceramics, LEDs, and even as a semiconductor in high-performance electronic devices.