Potassium bromide (KBr) forms a cubic crystalline structure when it solidifies. This is a simple, highly symmetrical arrangement of ions.

Here's a breakdown:

* Cubic: The basic unit of the structure is a cube with potassium ions (K+) at the corners and bromide ions (Br-) at the center of each face.

* Crystalline: The ions are arranged in a highly ordered, repeating pattern. This structure is what gives potassium bromide its characteristic properties.

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