`MnF_(7)` is not stable while `Mn_(2)O_(7)` is stable.

Explanation

To understand why \( \text{MnF}_7 \) is not stable while \( \text{Mn}_2\text{O}_7 \) is stable, we can break down the reasoning into clear steps:

### Step 1: Analyze the Composition of Each Compound
- **\( \text{MnF}_7 \)** consists of one manganese (Mn) atom and seven fluorine (F) atoms.
- **\( \text{Mn}_2\text{O}_7 \)** consists of two manganese (Mn) atoms and seven oxygen (O) atoms.

### Step 2: Consider the Electronegativity of the Atoms
- Fluorine is the most electronegative element, which means it has a strong tendency to attract electrons. This high electronegativity leads to significant electron-electron repulsion when multiple fluorine atoms surround a central atom.
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