title: Correlation between the hard and soft character and the visible absorption spectra of Xylenol Orange and Methylthymol Blue complexes with bivalent metal ions.
abstract: The changes in the spectra of Xylenol Orange and Methylthymol Blue complexes with several bivalent metal ions have been investigated in terms of the chemical bonding between the phenolic oxygen atom and the metal ion, and the hard and soft character of the donor and acceptor. The value of this approach to indicator action is discussed.
authors.affiliation: Department of Chemical Technology, Faculty of Engineering, Yamaguchi University, Tokiwadai, Ube 755, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Murakami
authors.forename: T
authors.initials: T
authors.lastname: Yoshino