Tetrahedral voids are located on a distance 1/4 of the body diagonal from corner and octahedral void is located on a distance 1/2 of body diagonal from cornersince length of body diagonal is √3atherefore t.v is located at a distance √3a/4 from corner and o.v at a distance √3a/2 from corner...distance between t.v and o.v =√3a/4=.433a

Introduction:
In a face-centered cubic (fcc) lattice, there are two types of voids: tetrahedral and octahedral. The distance between these two voids plays an important role in determining the properties of the lattice.

Tetrahedral Void:
A tetrahedral void is a space between four atoms that form a tetrahedron. These voids are located at the center of each face of the cube. The distance between two adjacent tetrahedral voids can be determined by the following equation:

Distance between tetrahedral voids = √2 × r

where r is the radius of the atoms in the lattice.

Octahedral Void:
An octahedral void is a space between six atoms that form an octahedron. These voids are located at the center of the cube. The distance between two adjacent octahedral voids can be determined by the following equation:

Distance between octahedral voids = √2 × r

where r is the radius of the atoms in the lattice.

Distance between Tetrahedral and Octahedral Voids:
The distance between a tetrahedral void and an adjacent octahedral void can be determined by the following equation:

Distance between tetrahedral and octahedral voids = √3 × r

The distance between tetrahedral and octahedral voids is important because it determines the size of the interstitial sites in the lattice. These interstitial sites can be occupied by impurity atoms or small molecules, which can affect the properties of the lattice.

Conclusion:
In an fcc lattice, the distance between tetrahedral voids and octahedral voids can be calculated using simple equations that depend on the radius of the atoms in the lattice. This distance is important because it determines the size of the interstitial sites in the lattice, which can be occupied by impurities or small molecules.