The Formation Constant and Thermodynamic Parameters of Mn2+, Co2+, Ni2+, Cu2+ and Zn2+ Chelates Formed with Dithiodiglycolic Acid

Abstract

pH-Measurements have been made for determination of formation constants of the Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺ chelates with dithiodiglycolic acid (DTDGA) at different temperatures 20º, 30º and 40ºC and varying ionic strengths 0.1, 0.2, 0.5 and 1M KNO₃ by employing Calvin-Melchior's extension of Bjerrum's method in aqueous media. Thermodynamic parameters for chelation processes have also been calculated. The formation constants are discussed in relation with atomic properties.