Formulae for ortho-, pyro-, chain-, and double chain silicates are respectively:

Options

A. `[SiO_(4)]^(4-), [Si_2O_7]^(6-),[Si_2O_3]^(2-),[SiO_11]^(6-)`
B. `[SiO_(4)]^(4-), [Si_2O_7]^(6-),[SiO_3]^(2-),[Si_(4)O_11]^(6-)`
C. `[SiO_(4)]^(4-), [Si_2O_7]^(4-),[SiO_3]^(2-),[SiO_11]^(6-)`
D. `[SiO_(4)]^(4-), [Si_2O_6]^(6-),[SiO_3]^(2-),[SiO_11]^(6-)`

Explanation

To solve the question regarding the formulas for ortho-, pyro-, chain-, and double chain silicates, we will analyze each type of silicate and derive their respective formulas step by step.

### Step-by-Step Solution:

1. **Ortho-silicate:**
- Ortho-silicates are the simplest form of silicates where no oxygen atoms are shared between the tetrahedral units.
- Each tetrahedron consists of one silicon atom (Si) surrounded by four oxygen atoms (O).
- The formula for ortho-silicate is:
\[ \text{SiO}_4^{4-} \]

2. **Pyro-silicate:**
- In pyro-silicates, two tetrahedral units share one oxygen atom.
- This sharing results in a structure that can be represented as two SiO4 tetrahedra connected through one shared oxygen.
- The formula for pyro-silicate is:
\[ \text{Si}_2\text{O}_7^{6-} \]

3. **Chain silicate:**
- Chain silicates involve the sharing of two oxygen atoms between tetrahedral units, forming a chain-like structure.
- Each unit in the chain can be represented as SiO3.
- The formula for chain silicate is:
\[ \text{SiO}_3^{2-} \]

4. **Double chain silicate:**
- In double chain silicates, three oxygen atoms are shared between tetrahedral units, leading to a more complex structure.
- The formula for double chain silicate can be represented as:
\[ \text{Si}_4\text{O}_{11}^{6-} \]

### Summary of Formulas:
- Ortho-silicate: \(\text{SiO}_4^{4-}\)
- Pyro-silicate: \(\text{Si}_2\text{O}_7^{6-}\)
- Chain silicate: \(\text{SiO}_3^{2-}\)
- Double chain silicate: \(\text{Si}_4\text{O}_{11}^{6-}\)

### Final Answer:
The formulas for ortho-, pyro-, chain-, and double chain silicates are respectively:
- \(\text{SiO}_4^{4-}\)
- \(\text{Si}_2\text{O}_7^{6-}\)
- \(\text{SiO}_3^{2-}\)
- \(\text{Si}_4\text{O}_{11}^{6-}\)