FT‐Raman and FT‐IR spectroscopic study of synthetic Mg/Zn/Al‐hydrotalcites

Abstract Synthetic Mg/Zn/Al‐hydrotalcites with atomic ratios of 6:0:2, 4:2:2, 2:4:2 and 0:6:2 were characterized by FT‐Raman and FT‐IR spectroscopy. ‘AlOH’ IR translation modes are observed at 419, 427, 559, 616 and 771 cm −1 with two corresponding Raman bands at 465–477 and 547–553 cm −1 . ‘MgOH’ IR translation modes are found at 412, 559 and 616 cm −1 with equivalent Raman bands at 464–477 and 547–553 cm −1 . The ‘ZnOH’ IR translation mode is found at 445 cm −1 and the Raman modes around 450 and 495 cm −1 . The CO 3 2 − group is identified by the ν 1 (IR) at 1112 cm −1 and a doublet in the Raman around 1045–1055 and 1060 cm −1 . ν 2 (IR) is observed at 874 cm −1 . ν 3 (IR) is a doublet at 1359 and 1381 cm −1 . ν 4 is observed in both the IR and Raman spectra around 670 and 695–715 cm −1 , respectively. In the OH deformation region, a doublet is observed for ‘AlOH’ at 955 and 1033 cm −1 in the IR spectra. The ‘ZnOH’ IR deformation mode is observed at 1462 cm −1 . H 2 O is characterized by a bending mode at 1632 cm −1 and an H‐bonded interlayer H 2 O mode at 3266 cm −1 with a Raman band between 3244 and 3271 cm −1 . The OH stretching region is characterized by three bands in the Raman spectra around 3355–3360, 3440–3455 and 3535–3580 cm −1 . One band is observed in the IR spectra at 3471 cm −1 . Copyright © 2004 John Wiley & Sons, Ltd.