Question

An element has a face-centred cubic (fcc) structure with a cell edge of a. The distance between the centres of two nearest tetrahedral voids in the lattice is ______.

Options

• a

• `3/2  a`

• `a/2`

• `sqrt 2  a`

Answer 1

An element has a face-centred cubic (fcc) structure with a cell edge of a. The distance between the centres of two nearest tetrahedral voids in the lattice is `bbunderline(a/2)`.

Explanation:

In a face-centred cubic (fcc) or cubic close-packed (ccp) structure, tetrahedral voids are located along the edge of the cube, specifically at `1/4` distance along the body diagonal between atoms. The distance between two nearest tetrahedral voids lies along the edge of the cube. So, the distance between the centres of two nearest tetrahedral voids is `a/2`.