The coordination number of Al in the crystalline state of $\mathrm{AlCl}_{3}$ is

JEE Advanced · 2009 · 12 Apr 2009 · Paper 2 · p-Block Elements

The coordination number of Al in the crystalline state of

AlCl_{3}

Answer: 6

In the solid state,

AlCl_{3}

exists in a layer structure where each Al atom is surrounded by 6 Cl atoms in an octahedral arrangement. The structure is similar to that of

CrCl_{3}

, with a cubic close-packed (ccp) arrangement of chloride ions and aluminum ions occupying octahedral voids.

JEE Advanced · 2009 · 12 Apr 2009 · Paper 2 · Integer answer