In a study of a ligand substitution reaction [MX4] negative +Y with negative exponent?

Question

gives [MX3Y] negative squared and X with a negative exponent,and species [MX4Y] with negative exponent is identified via its characteristic visible spectrum. Is this reaction likely to be associative(A), dissociative(D),Interchange(I) or there in no any conclusion?

Answer 1

Those aren't exponents, they're charges. X-2 means X with a -2 charge on it.