What are the three categories of atomic solids?

Imagine a metallic solid as a structure where countless atoms come together like a vast, sprawling city. The unique connection between these atoms is known as a metallic bond. It is akin to a communal sharing of outer electrons creating what's often referred to as an 'electron sea'. This fluid communal electron cloud provides metallic solids with some of their most eminent properties like exceptional electrical conductivity, malleability, and a notable luster.

Within this 'electron sea', electrons are free to move about, which does wonders for the conductivity of metals. The malleable nature of metallic bonds allows them to be hammered into sheets or drawn into wires without breaking, due to their ability to undergo deformation. This capacity to bend and shape is crucial for countless applications from industrial building materials to intricate jewelry design. Moreover, the 'sea of electrons' absorbs and releases light, giving metals their signature sheen that we often admire.

In contrast to the communal aspect of metallic bonds, network covalent solids are akin to a strong, tight-knit family. The bonds within these solids are the covalent bonds, which are like very strong handshakes between atoms, where they share pairs of electrons. These shared pairs of electrons generate extremely strong and stable connections.

Exemplars of Resilience

Like the diamond, the archetypal network covalent solid, these structures exhibit impressive hardness due to the rigorous 3D network of covalently bonded atoms. Their structure also imparts them with high melting points, though these solids typically do not conduct electricity like their metallic counterparts. This is due to the lack of free electrons, as all are tightly engaged in bonds. Applications of network covalent solids range from diamond-tipped cutting tools to silicon chips in computers, illustrating their indispensable role in both industry and technology.

Moving to the realm of van der Waals solids, we enter the world of the weakest type of interatomic forces. These solids are held together by van der Waals forces, which are gentle, fleeting attractions between atoms or molecules. In comparison to the strong bonds in metallic and network covalent solids, van der Waals forces are like the polite nods neighbors exchange -- enough to acknowledge each other but not strong enough to build a deep connection.

The temporary dipoles in these solids can lead to attractions known as London dispersion forces, which, while weak, are pivotal in holding these solids together. Due to these mild forces, van der Waals solids usually have low melting and boiling points and are often soft to the touch. They include materials such as noble gases in solid form and molecular solids like solid carbon dioxide, 'dry ice'. These materials are widely used for their sublime qualities, turning directly from solid to gas, and for preserving biological samples due to their extremely low temperatures when in solid form.