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Solids, as opposed to liquids and gases, have a number of distinguishing properties that distinguish them from one another. Their ability to withstand any force that is applied to their surface, for example, is one example.
Solids are classified into several categories:—
Solids are categorised into two sorts based on the arrangement of its constituent particles:
- Crystalline solid
- Amorphous solid
Crystalline solids are further subdivided into four groups based on the nature of the intermolecular forces or chemical bonding that exists between them.
They are, in fact.
1.Molecular Solids
2.Ionic solids
3.Metallic solids
4.Covalent solids
When it comes to molecular solids, the elementary particles of matter are referred to as molecules.
Molecules exist because they are tightly packed and structured in such a way that they form a molecular solid when compressed.
Classification of solids on the basis of Binding Forces
- Polar Molecular Solids
- Molecular Solids that are non polar
- Molecular Solids with Hydrogen Bonding
1. Polar Molecular Solids
Polar Molecular Solids are solid substances in which molecules are bound together by strong dipole-dipole forces, and they are found in a wide variety of natural and synthetic materials.
Polar Molecular Solids are soft and flexible in their natural state.
Polar Molecular Solids, often known as insulators, do not conduct electricity and therefore do not conduct electricity.
In general, the melting point of Polar Molecular Solids is higher than that of Non-Polar Molecular Solids when compared to the latter.
For example, (NH3) Ammonia and (SO2) Sulphur Dioxide are both nitrogen-containing compounds.
Non-polar Molecular Solids
Non-Polar Molecular Solids are solid things in which molecules are produced from atoms of the same kind, and these solid objects are known as Non-Polar Molecular Solids.
The dipole moment of Non-Polar Molecular Solids is zero, and the forces acting on them are not as strong as the London dispersion forces that exist between the constituent molecules.
The following features of non-polar Molecular Solids are discussed:
- This form of Molecular Solid has a soft consistency.
- They do not conduct electricity since they are nonconductors.
- Non-Polar Molecular Solids are composed of molecules with low melting points.
For example, hydrogen (H2), iodine (I2), and chlorine (Cl) are all elements (Cl2).
Hydrogen-Bonded Molecular Solids (HBM Solids)
The forces inherent in Hydrogen-Bonded Molecular Solids, which are referred to as Hydrogen Bonds, are known to be responsible for the attraction of molecules between them.
When compared to the melting and boiling points of polar and non-polar types of molecular solids, the melting and boiling temperatures of this form of molecular solid are significantly greater.
Hydrogen-Bonded Molecular Solids exhibit the following characteristics:
At typical room temperature and pressure, Hydrogen-Bonded Molecular Solids behave as soft liquids or volatile liquids, respectively.
They are non-conductors of electricity and can also be referred to as insulators in some circles.
For example, ice (H2O).
Solids can be classed according to the types of bonds that hold the atoms or molecules together in the solid state-
Solids are classified according to their molecular, covalent, ionic, or metallic composition using this approach.
Molecular solid
A molecular solid is a solid made up of discrete molecules that has the properties of a liquid.
Van der Waals forces, dipole-dipole interactions, quadrupole interactions, -interactions, hydrogen bonding, halogen bonding, London dispersion forces, and, in some molecular solids, coulombic interactions are the cohesive forces that hold the molecules together.
Van der Waals forces are the cohesive forces that hold the molecules together.
Molecular solids are weak electrical conductors, yet some, such as TTF-TCNQ, are semiconductors (with a conductivity of 5 x 102 cm), which is a rare occurrence.
They are still significantly less than the conductivity of copper (which is 6 x 105 cm), which is a significant difference.
If you compare Molecular Solids to metals (iron), ionic compounds (sodium chloride), and covalent compounds, they have lower melting (Tm) and boiling (Tb) points (diamond).
Among the molecular solids with low melting and boiling temperatures are argon, water, naphthalene, nicotine, and caffeine.
Molecular solids are composed of a variety of elements ranging in size from condensed monatomic gases to small molecules (for example, naphthalene and water) to massive molecules with tens of atoms or more (i.e. fullerene with 60 carbon atoms).
Covalent solid
Covalent solids, such as diamond, crystallise and may be thought of as a single big molecule made up of an almost infinite number of covalent bonds.
Covalent solids, such as diamond, can be thought of as a single giant molecule made up of an almost unlimited number of covalent bonds.
Diamond is composed of four carbon atoms that are covalently bonded to one another and orientated toward the corners of a tetrahedron.
Each carbon atom in diamond is covalently bound to four other carbon atoms.
Ionic solid
NaCl is an example of an ionic solid, which is held together by the strong attraction between ions of opposite charges.
Because the strength of an ionic bond is proportional to the square of the distance between the positive and negative charges, the radii of the ions that make up the solid are proportional to the strength of the force of attraction.
As the size of these ions increases, the strength of the link weakens.
Metallic solid
The first step in understanding metallic solids is to dispel a widespread misperception about chemical bonds.
Ionic and covalent bonds are frequently portrayed as if they were the two extremities of a two-dimensional bonding paradigm, with substances containing polar bonds falling somewhere in between the two extremes.
Conclusion
Solid-state is simply one of the states of matter, and there are many others.
We learned in our early schooling that matter may exist in three states:
solid, liquid, and gas – and that each state has its own properties.
In contrast, when we graduate from lower to higher levels of education, the concepts become more complex, and there are more things to learn.
The notion of solid-state will be discussed in greater depth in this lesson, and we will learn all of the underlying concepts, as well as the qualities and different types of solids, in order to fully comprehend the concept.
Molecular solids are a type of solid that is made up of molecules.
Molecular solids are distinguished by the presence of relatively strong intramolecular bonds between the atoms that make up the molecules, as well as significantly weaker intermolecular connections between the molecules themselves.
Molecular solids are frequently soft substances with low melting temperatures due to the weak intermolecular interactions that exist between the molecules.
