Why does `NH_3` form hydrogen bond but `PH_3` does not?

Explanation

To understand why NH₃ (ammonia) forms hydrogen bonds while PH₃ (phosphine) does not, we can break down the explanation into a series of logical steps:

### Step-by-Step Solution:

1. **Definition of Hydrogen Bonding**:
- Hydrogen bonding occurs when a hydrogen atom covalently bonded to a highly electronegative atom (like nitrogen, oxygen, or fluorine) experiences an attraction to another electronegative atom.

2. **Electronegativity Comparison**:
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