Hydrolysis of Trivalent Holmium in Aqueous Solutions of 2 M Ionic Strength by Spectrophotometric and Potentiometric Methods

Miguel Angel Hernández-García^1,2, Hilario López-González^1*, Alberto Rojas-Hernández²

¹Departamento de Química, Gerencia de Ciencias Básicas, Dirección de Investigación Científica, Instituto Nacional de Investigaciones Nucleares, México D.F., México.
²Area de Química Analítica, Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, México D.F., México.

DOI: 10.4236/ampc.2015.55017                

Abstract

The first hydrolysis constants of trivalent holmium in 2 M NaClO₄ and 2 M NaCl at 303 K and in CO₂ free conditions were determined. The pC_H borderlines of precipitation and first hydrolysis were determined by means of a spectrophotometric method and last one with the program SQUAD. Independently, the stability constant for the first hydrolytic species was determined, by means of potentiometric pH titrations whose data were treated with the program SUPERQUAD. The hydrolysis constants obtained were:  and . These values attained by both methods are the same. The log₁₀β_1,Cl constants for the species HoCl²⁺ was also calculated for 2 M ionic strength and 303 K from the hydrolysis constant obtained in both perchlorate and chloride media. This value was logβ_1,Cl = -0.56.

Keywords

Holmium, Hydrolysis, Spectrophotometric, Potentiometric, Chloride of Holmium Specie

Conflicts of Interest

The authors declare no conflicts of interest.

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