Which of the following species does not exist?

Options

A. `[BF_6]^(3-)`
B. `[Al F_6]^(3-)`
C. `[GaF_6]^(3-)`
D. `["In" F_6]^(3-)`

Explanation

To determine which of the following species does not exist, we will analyze each option: BF6^3-, AlF6^3-, GaF6^3-, and InF6^3-.

### Step-by-Step Solution:

1. **Identify the Central Atom and its Coordination Number**:
- All the species listed involve a central atom (Boron, Aluminum, Gallium, Indium) surrounded by six fluoride ions (F^-). This indicates a coordination number of 6.

2. **Analyze Boron (B)**:
- Boron has an atomic number of 5 with the electron configuration of 1s² 2s² 2p¹. In its ground state, it has no d-orbitals available for bonding.
- Since boron lacks empty d-orbitals, it cannot accommodate additional electrons from six fluoride ions to form BF6^3-.

3. **Analyze Aluminum (Al)**:
- Aluminum has an atomic number of 13 and possesses the electron configuration of 1s² 2s² 2p⁶ 3s² 3p¹. It has available d-orbitals in the third shell.
- Therefore, Al can form AlF6^3-.

4. **Analyze Gallium (Ga)**:
- Gallium has an atomic number of 31 with the electron configuration of [Ar] 3d¹⁰ 4s² 4p¹. It also has d-orbitals available.
- Thus, Ga can form GaF6^3-.

5. **Analyze Indium (In)**:
- Indium has an atomic number of 49 with the electron configuration of [Kr] 4d¹⁰ 5s² 5p¹. It has d-orbitals available as well.
- Hence, In can form InF6^3-.

6. **Conclusion**:
- Out of the four species, BF6^3- cannot exist due to the absence of empty d-orbitals in boron. The other three species (AlF6^3-, GaF6^3-, and InF6^3-) can exist because their central atoms have available d-orbitals.

### Final Answer:
**BF6^3- does not exist.**