Oxy anion(s) containing (6,2) pair of equivalent X-O linkaes (where X-central atom) is/are:

Options

A. `S_(2)O_(8)^(2-)`
B. `P_(2)O_(6)^(4-)`
C. `P_(2)O_(7)^(4-)`
D. `P_(2)O_(8)^(4-)`

Answer

To solve the question regarding oxyanions containing (6,2) pairs of equivalent X-O linkages, we will analyze the given options step by step.

### Step 1: Understand the Question
The question asks for oxyanions that have 6 pairs of equivalent X-O linkages and 2 pairs of equivalent exo linkages, where X is the central atom.

### Step 2: Analyze the Options
We have four options to analyze:
1. Si2O8
2. P2O4O6^4-
3. P2O7^4-
4. P2O8^4-

### Step 3: Examine Each Oxyanion

#### Option 1: Si2O8
- The structure of Si2O8 involves two silicon atoms bonded to eight oxygen atoms.
- Due to resonance, we can determine that there are 6 equivalent Si-O bonds.
- Additionally, we can identify 2 pairs of equivalent exo linkages.
- **Conclusion**: This option satisfies the condition.

#### Option 2: P2O4O6^4-
- The structure involves two phosphorus atoms and multiple oxygen atoms.
- Upon analysis, we find that there are no equivalent exo linkages present.
- **Conclusion**: This option does not satisfy the condition.

#### Option 3: P2O7^4-
- The structure contains two phosphorus atoms linked to seven oxygen atoms.
- There are 6 equivalent P-O bonds due to resonance.
- Additionally, we can identify 2 pairs of equivalent exo linkages.
- **Conclusion**: This option satisfies the condition.

#### Option 4: P2O8^4-
- The structure consists of two phosphorus atoms and eight oxygen atoms.
- Similar to the previous options, we find 6 equivalent P-O bonds due to resonance.
- There are also 2 pairs of equivalent exo linkages.
- **Conclusion**: This option satisfies the condition.

### Step 4: Final Conclusion
Based on the analysis:
- **Correct Answers**: Options 1 (Si2O8), 3 (P2O7^4-), and 4 (P2O8^4-) contain the required (6,2) pairs of equivalent X-O linkages.