In chromium (III) chloride, CrCl_3, chloride ions have cubic close packed arrangement and Cr (III) ions are present in the octahedral holes. What fraction of the octahedral holes is occupied ? What fraction of total number of holes is occupied ?

In chromium (III) chloride, CrCl_3, chloride ions have cubic close pac

1.	In chromium (III) chloride, CrCl_3, chloride ions have cubic close packed arrangement and Cr (III) ions are present in the octahedral holes. What fraction of the octahedral holes is occupied ? What fraction of total number of holes is occupied ?
Answer» Solution :Suppose number of atoms Q=N Then number of tetrahedral sites =2 n `therefore` Number of atoms P=2n `therefore` Ratio P:Q=2n:n =2 :1 , i.e., FORMULA is `P_2Q`