ABSTRACT
Nickel salts (acetate, chloride and nitrate) are of everyday use in laboratories of inorganic and organic syntheses. In the process of obtaining oxides, hydroxides and oxy-hydroxides of nickel for the most diverse applications (batteries, pigments, sensors and electrocatalysis for example) it is necessary to understand the characteristics, the structural and electronic properties, that each precursor salt can confer to the final product. Premised carry out an assessment of the structural, spectroscopic and thermal behavior of nickel salts. Profile X-ray diffraction (XRD) enabled the identification of the crystal lattice and its parameters. Spectroscopic data (UV-Vis) show the similarity of solution absorption bands assigned in accordance with the permitted and prohibited transitions to hexa(aqua)nickel(II) ion. However, the spectra differ when evaluating the solids by diffuse reflectance. Fact that enables to calculate the band gap energies for each salt; value of 2.85 eV for acetate, 2.46 eV for chloride and 2.61 eV for nitrate. Color data (L*a*b*) can predict the green ton of intensity decreases in the sequence: nitrate> chloride> acetate. Curves thermal (TG-DTA) infer purity and quantify the number of hydration water molecules, consistent with the supplier information. Morphological analysis (SEM) and structural (XRD) of the particles generated in the thermal curves allow to determine the estimated residual NiO composition, more precisely to the derivative of nickel nitrate (NiO1.1) whose particle size is of the order of 0.1 μm, the smaller size from the waste.
Keywords:
Nickel salts; Characterization; Spectroscopy; Colorimetry
