Diffuse Reflection Infrared Fourier Transform (DRIFT) Spectra and High-Temperature DRIFT Spectra of β—Ni(IO 3 ) 2 ·4H 2 O,Ni(IO 3 ) 2 ·2H 2 O,Mg(OH) 2,and Zn(OH)F: Novel Embedding Materials

Abstract

Diffuse reflection infrared Fourier transform (DRIFT) spectra of the hydroxides Mg(OH)₂ and Zn(OH)F and the iodate hydrates β–Ni(IO₃)₂·4H₂O and Ni(IO₃)₂·2H₂O have been recorded at ambient and high temperature. Spectra without shifts of the band maxima compared to those of conventional infrared transmission spectra and without inversion of the bands were obtained by dilution of the compounds to about 2–10% with an appropriate embedding material. α–Al₂O₃, TiO₂, ZrO₂, PbF₂, MgO, BaO, ZnO, Na₂SiO₃, SiO₂ (aerosil), and powdered copper, aluminum, and magnesium were tested as diluents for hydrates and hydroxides, especially at elevated temperatures, as alternatives for the commonly used KBr. Thus, α–Al₂O₃, PbF₂, and powdered copper were established as the most favorable diluents. Using these novel embedding materials, high-temperature DRIFT spectra are obtainable at temperatures not accessible with KBr discs. Dehydration and decomposition of the iodate hydrates under study were shown by change or disappearance of the respective water bands.