# Voids

The word "void" refers to space between constituent particles. Solids can be packaged in one of three ways as follows:

1. One-dimensional (1D) tight packing

2. Two-dimensional (2D) close packing

3. Three-dimensional (3D) close packing.

When atoms are arranged in a square close packing of a hexagonal close packing, we can see spaces between them in 2-dimensional structures.

The absence of material, or an area devoid of materials where not intended.

The empty space present between the constituents particles in a close packed structure

•    Containing no matter; empty.
•    Not occupied; unfilled.
•    Completely lacking; devoid: void of understanding. See Synonyms at empty.
•    Ineffective; useless.

## Types of Void

### 1. Trigonal voids:

These triangular voids are seen in two different orientations in hexagonal packing. The apex of the triangle in one row points upward, while the apex of the triangle in the other row points downward.

### 2.Tetrahedral voids :

In a cubic close-packed structure (3-D), the second layer's spheres are above the first layer's triangular voids. Every sphere touches the first layer's three spheres. It forms a tetrahedron by joining the centers of these four spheres and the space created by joining the centers of these spheres forms a tetrahedral void.

### 3. Octahedral Voids :

In a three-dimensional structure (3-D), octahedral voids are located next to tetrahedral voids. When the triangular voids of the first layer coincide with the triangular voids of the layer above or below it, we see a void that is formed by enclosing six spheres. This vacant space formed by combining the triangular voids of the first layer and that of the second layer is called Octahedral Voids.