Question

Which of the following is not true?

• A. All unit cells are primitive
• B. FCC structure is a closed packed structure
• C. A unit cell is primitive if it contains lattice points only at its corner
• D. A lattice does not contain any atom or molecule

Answer 1

Answer: (D)

A crystal structure is composed of a unit cell, a set of atoms arranged in a particular way, which is periodically repeated in three dimensions on a lattice. A primitive unit cell of a particular crystal structure is the smallest possible unit cell one can construct such that, when tiled, it completely fills space. The spacing between unit cells in various directions is called its lattice parameters.