A compound is formed by two elements \(P\) and \(Q\). The element \(Q\) forms ccp and atoms \(P\) occupy \(1/3 \)rd of tetrahedral voids. What is the formula of the compound?

\(P_2Q_3\)

The correct answer is option 1. \(P_2Q_3\).

To determine the formula of the compound, we need to analyze the given information:

Element \(Q\) forms a ccp (cubic close-packed) structure.

In a ccp structure, there are 4 atoms of \(Q\) per unit cell.

Element \(P\) occupies \(\frac{1}{3}\)rd of the tetrahedral voids.

In a ccp structure, the number of tetrahedral voids is twice the number of atoms in the unit cell. Hence, there are \(2 \times 4 = 8\) tetrahedral voids per unit cell.

Since \(P\) occupies \(\frac{1}{3}\) of the tetrahedral voids:

\(\text{Number of } P \text{ atoms} = \frac{1}{3} \times 8 = \frac{8}{3} \approx 2.67 \text{ atoms per unit cell}\)

For \(Q\), there are 4 atoms per unit cell.

For \(P\), we have calculated approximately 2.67 atoms per unit cell.

To simplify, let's assume the smallest whole number ratio:

Multiply the number of \(P\) atoms by 3 to eliminate the fraction:

\(P : Q = 2.67 : 4 \approx 8 : 12\)

Simplifying the ratio:

\(P : Q = 2 : 3\)

The empirical formula of the compound based on the ratio is \(P_2Q_3\).

The correct answer is option 1: \(P_2Q_3\).