Infrared study of magnesium-nickel hydroxide solid solutions

The IR spectra of the co-precipitated solid solutions MgxNi1-x(OH)(2) were studied in the 4000-40 cm(-1) region. The spectra as a whole resemble those of Mg(OH)(2) and beta-Ni(OH)(2), while certain differences are noted when compared with the spectra of the mechanically mixed samples Mg(OH)(2) + beta-Ni(OH)(2). Such a behavior may imply formations of mono-phase solid solutions which have a brucite-like crystal structure. The composition-dependent band shifts were observed for the fundamentals and this tendency is discussed in terms of polarization of the O-H bond and partial covalency of the M-O bonds. The gradual changes in band position of MgxNi(1-x)(OH)(2) (1.00 greater than or equal to x greater than or equal to 0.00) were used to assign the IR active lattice modes of the solid solutions and to review the assignment of beta-Ni(OH)(2). (C) 2002 Elsevier Science B.V. All rights reserved.