Write a distinguishing feature of metallic solids.

Explanation

**Step-by-Step Text Solution:**

1. **Definition of Metallic Solids**: Metallic solids are a type of solid where metal cations are surrounded by a sea of delocalized electrons. This structure allows for various unique properties.

2. **Distinguishing Feature**: One of the most distinguishing features of metallic solids is their ability to conduct heat and electricity. This is due to the presence of free-moving delocalized electrons that can carry charge and energy throughout the solid.

3. **Additional Properties**: In addition to electrical and thermal conductivity, metallic solids are also characterized by their malleability (ability to be hammered into thin sheets) and ductility (ability to be drawn into wires).

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