In CaF2 type (fluorite structure), Ca2+ ions form_(A)_ structure and F- ions are present in all_(B)_ voids. The coordination number of Ca2+ is (C) and F- is (D). (A), (B), (C) and (D) respectively are:
A. (A)- ccp; (B)- octahedral; (C)- 8; (D)- 4
B. (A)- bcc; (B)- tetrahedral; (C)- 4; (D)- 8
C. (A)- ccp; (B)- tetrahedral; (C)- 8; (D)- 4
D. (A)- ccp; (B)- octahedral; (C)- 4; (D)- 8

In the given question, we are talking about the structure of calcium fluoride (CaF₂), which crystallizes in a fluorite structure. Let's break down the information:

### Step 1: Structure of CaF₂ (Fluorite Structure)
- In a **CaF₂ (fluorite structure)**, the **Ca²⁺ ions form a cubic close-packed (ccp) structure**. This means that the calcium ions are arranged in a face-centered cubic (FCC) lattice. So, for part (A), the structure formed by \( Ca^{2+} \) ions is **ccp**.

### Step 2: Void Occupation by F⁻ Ions
- The fluoride ions (F⁻) occupy all the **tetrahedral voids** in this ccp structure. In the FCC arrangement, there are 8 tetrahedral voids per unit cell. So, for part (B), the voids occupied by \( F^- \) ions are **tetrahedral**.

### Step 3: Coordination Number of Ca²⁺ and F⁻
- Each \( Ca^{2+} \) ion is surrounded by 8 \( F^- \) ions in a cubic geometry, meaning the coordination number of \( Ca^{2+} \) is **8**.
- Each \( F^- \) ion is surrounded by 4 \( Ca^{2+} \) ions in a tetrahedral geometry, meaning the coordination number of \( F^- \) is **4**.

### Conclusion:
- (A) \( Ca^{2+} \) forms a **ccp** structure.
- (B) \( F^- \) ions are present in all **tetrahedral** voids.
- (C) The coordination number of \( Ca^{2+} \) is **8**.
- (D) The coordination number of \( F^- \) is **4**.

Thus, the correct answer is:
**C. (A)- ccp; (B)- tetrahedral; (C)- 8; (D)- 4**.