.sub.p3 +.sigma..sub.p4 +.sigma..sub.p5+.sigma..sub.p6 +.sigma..sub.p7 +.sigma..sub.p8, then Y.ltoreq.-0.08 when Z' is an oxygen atom and Y.ltoreq.-0.15 when Z' is a sulfur atom;X represents an electrical charge balancing counter ion; andn is the value required to neutralize the electrical charge, and at least one compound represented by the general formula (II): ##STR62## wherein, Q represents a