Let's analyze the given molecules to determine the one that has the maximum number of a-x bonds of identical length, where 'a' is the central atom and 'x' is the surrounding atoms.
(a) SFO: This molecule's molecular formula is not standard or widely recognized. It seems to be an unspecified or incorrect notation.
(b) IF7 (Iodine heptafluoride): In IF7, iodine (I) is the central atom surrounded by seven fluorine (F) atoms.
(c) PF5 (Phosphorus pentafluoride): In PF5, phosphorus (P) is the central atom surrounded by five fluorine (F) atoms.
(d) ClO4- (Perchlorate ion): In ClO4-, chlorine (Cl) is the central atom surrounded by four oxygen (O) atoms in a tetrahedral arrangement, and one oxygen atom carries a negative charge.