* Electronegativity Difference: Lanthanum (La) is a metal with a low electronegativity, while bromine (Br) is a nonmetal with a high electronegativity. The significant difference in electronegativity (around 1.9) leads to a transfer of electrons from La to Br, resulting in the formation of ions.

* Ionic Bonding: Lanthanum loses three electrons to form a +3 cation (La³⁺), while bromine gains one electron to form a -1 anion (Br⁻). These oppositely charged ions are then attracted to each other through electrostatic forces, forming the ionic compound LaBr3.

In summary, the large electronegativity difference between La and Br, leading to the formation of ions and subsequent electrostatic attraction, classifies LaBr3 as an ionic compound.