Solid Definition: Explained With Types & Properties

Solid is one of the many different states of matter. Solids have a unique shape, mass, and volume. The distinctive properties of solids set them apart from liquids and gases. Depending on how the particles are placed in a fixed or deterministic geometry, these solid states or shapes may exist. Solid ice, sugar, rock, etc. are examples of solids.

This Chemistry article teaches us a solid definition along with its types and properties in detail.

Solid Definition

Solids are defined as types of stuff that are hard in structure and resist changing their shape or volume. A solid’s closely linked particles make it impossible for them to move freely from one location to another. Due to their close proximity to one another, the particles continuously vibrate and twist but do not move. Solid ice, sugar, rock etc are examples of solids.

Solids have the strongest intermolecular attraction due to their fixed shapes and the fact that their constituent particles remain in place. Additionally, because there are already very few spaces between molecules, compressing a solid is very difficult.

Properties of Solid

Some main properties are as follows:

• Solids have fixed volume and solid shape.
• The distance between solids’ particles is small.
• Density is higher for solids in general.
• Strong intermolecular forces exist in solids.
• A solid diffusing into another solid move very slowly.
• A solid cannot flow.

Types of Solid

Amorphous solids and crystalline solids are the two types of solids which are explained below.

Amorphous Solid

Particles in amorphous solids lack a repeating lattice structure. They are also known as “pseudo solids.” Glass, rubber, gels, and the majority of polymers are examples of amorphous solids. Because the bonds do not break all at once, an amorphous solid does not have a fixed melting point. Instead, it melts gradually over a range of temperatures. This indicates that before becoming a liquid, an amorphous solid will first melt into a soft, flexible state.

Crystalline Solid

A solid whose components are arranged in a highly ordered microscopic structure to create a crystal lattice that extends in all directions is referred to as a crystal or crystalline solid.

They are anisotropic and also have different melting points. The actual solids are what we refer to them as. Diamond and benzoic acid are two examples of crystalline solids. The use of diamonds also extends to the cutting of glass and the creation of stunning jewellery.

Difference Between Crystalline and Amorphous Solids

Some main differences between amorphous and crystalline solids are discussed below.

Amorphous Solid	Crystalline Solid
Amorphous solids are also known as pseudo solids.	Crystalline solids are also known as true solids.
Amorphous solids’ constituent particles are not well arranged.	The component particles of crystalline material are well organized.
Amorphous solids have an irregular form and a poor particle arrangement.	Crystalline solids have clearly defined shapes and arrangements of their particles.
When heated, amorphous substances can be moulded into different shapes and gradually soften across a temperature range.	Crystalline substances have a definite melting point at which they start to melt.

Difference Between Solid, Liquid and Gas

In the below table, the differences between Solid Liquid and Gas are shown:

Solid	Liquid	Gas
It has a specific volume and shape.	It has a specific volume but no defined shape	It has no clear shape or volume.
Solids are already compact, so they cannot be further compressed.	The ability of liquids to be compressed is limited. But in order to compress liquids, great pressure or high temperature are needed.	Compressing gases is simple.
Solids have a high density because they have a distinct shape and volume.	Comparatively, liquids have a lower density than other liquids.	Gases have a lower density than solids and liquids.
The arrangement of the particles in solids exhibits a clear geometry.	Liquids lack a defined shape because liquids have looser particle arrangements than solids, which is why solids have a fixed shape.	Gases have poorly organized or compressed particles. Gases are hence shapeless.
Solids often do not expand much when heated.	When heated, liquids expand more than solids do.	When heated, gases expand more widely. When heated, they expand at the greatest rate.