What Is Stoichiometric Defect?

Are you curious to know what is stoichiometric defect? You have come to the right place as I am going to tell you everything about stoichiometric defect in a very simple explanation. Without further discussion let’s begin to know what is stoichiometric defect?

What Is Stoichiometric Defect?

Stoichiometric defects are defects in the composition of a crystal lattice that arise due to deviations from the ideal stoichiometry. Stoichiometry is the quantitative relationship between the elements in a compound, as expressed by its chemical formula. In a perfect crystal lattice, the ratio of the constituent atoms or ions is exactly as given by the formula. However, in reality, there may be deviations from this ideal composition, leading to stoichiometric defects.

Stoichiometric defects can occur due to a variety of reasons, including impurities in the crystal, vacancies or interstitial atoms, and non-stoichiometric chemical reactions during crystal formation. These defects can have a significant impact on the properties of the crystal, such as its electronic, optical, magnetic, and mechanical properties.

One of the most common types of stoichiometric defects is the Schottky defect, which involves the creation of paired vacancies of cations and anions in a crystal lattice. This can occur when the crystal is formed under non-stoichiometric conditions, such as in the presence of excess cations or anions. Schottky defects can lead to a decrease in the density and conductivity of the crystal.

Another type of stoichiometric defect is the Frenkel defect, which involves the displacement of an ion from its normal lattice site to an interstitial position. This can occur when the ion is small enough to fit into the interstitial space and can lead to an increase in the electrical resistivity and thermal conductivity of the crystal.

Stoichiometric defects can also affect the optical properties of a crystal. For example, color centers are created when an ion or molecule is missing from the crystal lattice, or when it is replaced by an impurity. The color center can absorb light of a specific wavelength, giving the crystal a characteristic color.


In conclusion, stoichiometric defects are a common phenomenon in crystals that can arise due to a variety of reasons. These defects can have a significant impact on the properties of the crystal and can be exploited for a range of applications, such as in optical and electronic devices. Understanding and controlling stoichiometric defects is therefore an important area of research in materials science and engineering.

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What Are Stoichiometric Defects Class 12?

Stoichiometric defects are intrinsic defects in which the ratio of cations to anions remains exactly the same as represented by the molecular formula. They are mainly two types: Vacancy defects in which an atom is not present at its lattice sites causing that lattice site to be vacant and creating a vacancy defect.

What Are Stoichiometric And Non-Stoichiometric Defects?

Stoichiometric defects are those that do not disturb the stoichiometry of a compound. Nonstoichiometric defects are defects in crystal structures that disturb the stoichiometry of the crystal. They do not affect the stoichiometry of the compound. They change the stoichiometry of the compound.

What Are Stoichiometric Defect Examples?

Ans-Vacancy and Schottky defects, both of which result in a drop in density, are examples of stoichiometric defects.

What Is Stoichiometric And Non-Stoichiometric Defect Class 12?

The non-stoichiometric defect is the type of point defect, and hence in this defect anion and cations are not equal in proportion, and large numbers of negative and positive charges are present. The non-stoichiometric defect is further divided into two classes that are metal excess defect and metal deficiency defect.

Which Is Not A Stoichiometric Defect?

Explanation for correct option: D. Metal deficiency defect.

How Are Stoichiometric Defects Classified?

Stoichiometric Defects

It is also called an intrinsic or thermodynamic defect. They are further classified into two types: Vacancy defect: (Vacant sites in the lattice) Interstitial defect: (Constituent particles move to the interstitial site of the lattice)

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What Is Stoichiometric Defect