Which of the following statement are correct for the ionic solids in which positive and negative ions are held by strong electrostatic attractive forces ?

Options

A. The radius ratio `r^(+)//r^(-)` increases as coordination number increases
B. As the difference in size of ions decreases, coordination number increases
C. When coordination number is eight, the `r^(+)//r^(-)` ratio lies between 0.225 to 0.414
D. In ionic solid of the type AX (ZnS, Wurtztite), the coordination number of `Zn^(++)` and `S^(2)` respectively are 4 and 4

Explanation

To determine which statements are correct regarding ionic solids where positive and negative ions are held by strong electrostatic attractive forces, we can analyze each statement based on the principles of ionic bonding and crystal structures.

### Step-by-Step Solution:

1. **Understanding Ionic Solids**: Ionic solids consist of positively charged cations and negatively charged anions. These ions are held together by strong electrostatic forces of attraction, which are significant due to the charges on the ions.

2. **Analyzing the First Statement**:
- The first statement mentions that the radius ratio (R+ / R-) increases as the coordination number increases.
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