In interhalogen compounds of the type Ab5 and AB7, B is invariably flourine,why ?
1 answer
The other halogen (I,Br, Cl) are large enough to accommodate 5 or 7 F atoms and have enough space for the extra pair of electrons (there are more than 8 around the B atom). However, note that IBr5 and BrCl5 (and others) are not "invariably" F.