which statement is wrong ?

Options

A. Beryl is an example of cyclic silicate
B. `Mg_2SiO_4` is othosilicate
C. Basic structural unit in silicates is the `SiO_4^(4-)` tetrahedron
D. Feldspars are not aluminosilicates

Answer

To solve the question of which statement is wrong, we need to analyze each of the given options carefully.

### Step-by-Step Solution:

1. **Option 1: Beryl is an example of cyclic silicate.**
- **Analysis:** Beryl has the chemical formula Be₃Al₂Si₆O₁₈ and is indeed classified as a cyclic silicate because it contains silicate rings. Each ring consists of SiO₄ tetrahedra linked together. Therefore, this statement is **correct**.

2. **Option 2: Mg₂SiO₄ is orthosilicate.**
- **Analysis:** The compound Mg₂SiO₄ is known as forsterite, which is an orthosilicate. In orthosilicates, the silicate tetrahedra (SiO₄) are not linked together but exist as discrete units. Therefore, this statement is also **correct**.

3. **Option 3: Basic structural unit in silicate is the SiO₄⁴⁻ tetrahedron.**
- **Analysis:** This statement is true as the basic structural unit of silicates is indeed the SiO₄ tetrahedron, which carries a -4 charge. Thus, this statement is **correct**.

4. **Option 4: Feldspars are not aluminosilicate.**
- **Analysis:** Feldspars are a group of minerals that are indeed classified as aluminosilicates because they contain aluminum (Al) along with silicon (Si) and oxygen (O). Therefore, stating that feldspars are not aluminosilicates is **incorrect**.

### Conclusion:
The wrong statement is **Option 4: Feldspars are not aluminosilicate**.