An ionic compound has a unit cell consisting of A ions at the corners of a cube, B ions on the centres of the faces of the cube but one axis of its faces are missing. The empirical formula for this compound would be -

• Correct answer
  A

  $\mathrm{A}{\mathrm{B}}_2$
• B

  ${\mathrm{A}}_3\mathrm{B}$
• C

  $\mathrm{A}\mathrm{B}$
• D

  ${\mathrm{A}}_2\mathrm{B}$

Hence, the correct answer is option: 'A'.