Influence of the Fe³⁺–for – Al³⁺Octahedral Substitutions on the IR Spectra of Montmorillonite Minerals

Hydrothermal synthesis of dioctahedral smectites: The Al–Fe3+ chemical series. Part II: Crystal-chemistry

“…These wavenumbers are consistent with those reported by Gates (2005) for natural smectites, whose δAl-Fe 3+ -OH band ranged from 868 to 870 cm −1 for nontronites and from 872 to 875 cm − 1 for beidellites. However, contrary to Craciun (1984) and Vantelon et al (2001), no linear correlation could be observed here between the Al- OH-Fe 3+ band wavenumber and Fe 3+ oct (Table 4). Marchel and Stanjek (2012) found a correlation between the δAl-Fe 3+ -OH band position and the tetrahedral charge of smectites.…”

The titration of clay minerals

“…These vibration positions are in good agreement with those given by Vantelon et al [23] for similar smectites. The position of the δ AlFeOH band agrees well with the band position given for montmorillonite by Craciun [27] as a function of Fe content (calculated value at 883 cm −1 ). Bands at 799 and 780 cm −1 are attributed to quartz [25].…”

Crystallochemical Study of a Population of Particles in Smectites from a Lateritic Weathering Profile

“…Samples show 3 absorption bands at 869, 843, and 821 cm -~, and a shoulder at 785 cm-L The 869 cm -l band is assigned to AIFeOH vibrations (Russell et al, 1970;Farmer, 1974). Cracium (1984) observed for montmorillonites a relationship between octahedral Fe 3 § content and the intensity and position of the absorption band due to A1OHFe vibrations. The wavenumber of A1OHFe vibrations band decreases with increasing octahedral Fe 3+ content to almost 880 cm -t or 870 cm -l. The 869 cm -1 band confirms the high octahedral Fe 3 § content of the samples.…”

“…In this case, Goodman et al (1976) attributed the band to A1OHFe vibrations, after rejecting, on the basis of M6ssbauer spectroscopic resuits, the possibility of assigning this band and the 820 cm -t one to vibrations of OH groups in trans and cis octahedral configurations. Alternatively, Russell et al (1970) and Cracium (1984) characterized an A13+OHMg 2 § vibration band at about 839-848 cm -l in montmorillonite. Taking into account all the crystallographic and chemical data, it seems that this last assignment should be retained here.…”