Voids in Solid State Definition

Voids Present in Solid-State

Closed Packed Structure 

Matter exists in a solid state due to the close packing of its constituent particles. There are two types of tight packing in solids. The two varieties are Cubic Close Packed (CCP) and Hexagonal Close Packed (hcp) lattices.

Closely Packed Cubic (CCP)

Due to the near proximity of the spheres of molecules in this packing, each row of spheres in a given dimension duplicates the previous row. The spheres in a row do not fit in the depressions formed by two adjacent spheres from the previous row. A typical arrangement is a term that refers to this particular form of layout. Additionally, this is referred to as a face-centered cubicle (FCC). Copper, silver, and gold are all metals with this type of dense packing of constituent particles.Simple cubic lattices are used for close-packed cubic

When atoms are placed in square close packing or hexagonal close packing in two-dimensional structures, we observe empty gaps between the atoms. These empty spaces are referred to as voids, and in hexagonal packing, these voids are triangular in shape, hence the name triangular voids lattices, while primitive cubic lattices are used for unit cells.

Hexagonal Close Packed (HCP)

The spheres of molecules in a single row are organized in such a way that they fit into depressions between neighboring spheres from the preceding row in this sort of packing. It is referred to as the ABAB layout. Numerous metals, including magnesium and zinc, have this type of packed lattice.

The coordination number refers to the number of neighboring atom particles. In both CCP and HCP, each sphere is surrounded by twelve surrounding atoms; thus, the coordination number is identical in both situations. 

Types of Voids

Tetrahedral Voids: Within a cubically close-packed structure, the second layer’s spheres are present above the first layer’s triangular voids. Each sphere touches the first of the layer’s three spheres. It forms a tetrahedron by the method of  joining the centers of these four spheres, and the space created by joining the centers of these spheres forms a tetrahedral void. In a closed packed structure, the number of tetrahedral voids is always two times that of the number of spheres. Let the number of spheres be n. Then the number of tetrahedral voids will be equal to 2n.

Characteristics

• Four atomic spheres enclose nothingness or empty space. 
• This void is generated when a triangular void composed of coplanar atoms comes into contact with the fourth atom above or below it.
• The volume of the void is significantly smaller than that of the spherical particles.
• If R is the radius of the constituent spherical particle, the radius of the tetrahedral vacuum is 0.225 R.
• The number of tetrahedral voids is equal to the number of densely packed spheres by a factor of 2N.

Octahedral Voids:   When these triangular voids of the first layer coincide with that of the triangular voids of those layer above or below it, we get a void that is formed by enclosing six spheres. This vacant paces which is formed by combining the triangular voids of the first layer and that of the second layer is called Octahedral Voids. Octahedral Voids can be referred to the space created by combining the triangular voids of the first and second layers. If the number of spheres  can you please buy, e fujita close-packed structure is n, then the number of octahedral voids will be n.

Characteristics

• Six atomic spheres encircle the void or nothingness. As a result, the coordination number of the tetrahedral vacancy is 6.
• Six atoms at each of the octahedron’s six corners interact with the atom in the octahedral void.
• This void is created by two pairs of equilateral triangles with six points pointing in opposing directions.
• The vacuum has a relatively small volume.
• If R is the radius of the constituent spherical particle, the radius of the octahedral vacuum is 0.414 R.
• The number of octahedral voids matches the number of spheres that are closely packed.

Conclusion

Voids are a technical term that refers to the spaces between constituent particles. In solid states, voids refer to the empty space between constituent particles in a densely packed system. In ccp and hcp structures, two types of voids are created. These are tetrahedral and octahedral voids, respectively. Tetrahedral voids are generated when a tetrahedron forms between atom layers.