Question

A cubic solid is made up of two elements $P$ and $Q.$ Atoms of $P$ are present at the corners of the cube and atoms of $Q$ are present by body centre. What is the formula of the compound and what are coordination number of $P$ and $Q$?

• A. $P{Q}_2,6:6$
• B. $P_2{Q}_2,6:6$
• C. $PQ,6:8$
• D. $PQ,8:8$

Answer 1

Answer: (D)

$PQ,8:8$

Since $P$ is present at corners of the cube,

So, number of $P$ atoms = $\frac{1}{8}\times 8=1$.

$Q$ is present at the body center. So, number of $Q$ atom = $1$.

So, the formula of the compound is $PQ$.

Here, $P$ is surrounded by 8 $Q$ atoms, and $Q$ is surrounded by 8 $P$ atoms.

So, the coordination number is $8:8$.

Hence, option "D" is the correct answer.