Estudio de la hidrólisis del ion Niquel(II) y de la formación de los complejos de Niquel(II) con los ácidos Picolínico y Dipicolínico en NaCl 1,0 mol.dm-3 a 25°C

Abstract

The hydrolysis products (hidroxylated complexes) of Nickel(II) ion and the complex species formed in aqueous solution (25oC, I = 1.0 mol.dm−3 NaCl ionic medium) between Ni(II) cation and the ligands: picolinic acid (Hpic) and dipicolinic acid (H2dipic), have been studied potentiometrically. In the application of the least-squares computer program, LETAGROP, to the experimental emf(H) data, were observed the formation of the hydrolysis products [Ni(OH)]+, [Ni(OH)2] and [Ni4(OH)4]4-. Additionally, were detected the formation of the complexes [Ni(pic)]+, [Ni(pic)2] and [Ni(pic)3]- with picolinic acid and the species [Ni(dipic)] and [Ni(dipic)2]2- with dipicolinic acid. The stability constants of the complexes formed were determined by potentiometric measurements.

Keywords

• Nickel(II) hydrolysis
• Nickel(II) complexes
• solution equilibria
• potentiometric studies
• stability constants
• speciation