Here's why:

* Electronegativity: Iodine (I) and bromine (Br) are both nonmetals and have relatively similar electronegativity values. This means they share electrons rather than one atom completely taking an electron from the other.

* Sharing of Electrons: In an IBr molecule, both iodine and bromine atoms share one electron each to form a single covalent bond. This sharing creates a stable molecule.

Additionally:

* While the electronegativity difference between iodine and bromine is small, bromine is slightly more electronegative than iodine. This means the shared electrons are slightly closer to the bromine atom, making the bond polar covalent. The bromine end of the molecule will have a slightly negative charge, and the iodine end will have a slightly positive charge.