Which of the following is correct structur of anion of pyrosilicates ?

Options

A.
B.
C.
D.

Answer

To determine the correct structure of the anion of pyrosilicates, we need to follow these steps:

### Step 1: Understand the Composition of Pyrosilicates
Pyrosilicates are composed of two tetrahedral silicate units. The basic unit of a silicate tetrahedron is represented as SiO4^4-. Therefore, when we have two tetrahedral units, we can represent the pyrosilicate anion as Si2O7^6-.

### Step 2: Draw the Structure of the Pyrosilicate Anion
To visualize the structure of the pyrosilicate anion (Si2O7^6-), we can draw it as follows:
- Start with two silicon (Si) atoms.
- Each silicon atom is surrounded by four oxygen (O) atoms, forming two tetrahedra.
- The tetrahedra share two oxygen atoms between them.

The structure can be represented as:
```
O
|
O - Si - O
| |
Si - O
|
O
```
In this structure, the shared oxygen atoms are represented by the bonds between the two silicon atoms.

### Step 3: Analyze the Given Options
Now that we have the structure of the pyrosilicate anion, we can compare it with the provided options:
1. **Option 1**: SiO4 (This represents a single tetrahedral silicate unit, not pyrosilicate)
2. **Option 2**: Represents the double tetrahedral silicate unit (Si2O7^6-), which is correct.
3. **Option 3**: Cyclic tetrahedral (This does not represent pyrosilicate)
4. **Option 4**: Chain tetrahedral (This also does not represent pyrosilicate)

### Step 4: Conclusion
From the analysis, we find that **Option 2** is the correct structure of the pyrosilicate anion.